# The correct kind of compression guage



## blsnelling (Mar 19, 2009)

This topic comes up every week and often more frequently. You absolutely *MUST *have a Schrader valve at the tip of your compression guage for use on a small 2-stroke engine. If it does not, you *cannot *use it, period. A Schrader valve is what's found in the stem of your car rims. The reason it is required is because of the small volume of these engines. It is not enough to pump up the pressure of the hose with every pull and you will end up with a way low reading. I wonder how many engines have been torn down that were perfectly fine? Some guages have a release valve up by the guage. That is *not sufficient *and *does not take the place *of the valve at the tip.

This is the valve that you *MUST *have.


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## barneyrb (Mar 19, 2009)

blsnelling said:


> This topic comes up every week and often more frequently. You absolutely *MUST *have a Schrader valve at the tip of your compression guage for use on a small 2-stroke engine. If it does not, you *cannot *use it, period. A Schrader valve is what's found in the stem of your car rims. The reason it is required is because of the small volume of these engines. It is not enough to pump up the pressure of the hose with every pull and you will end up with a way low reading. I wonder how many engines have been torn down that were perfectly fine? Some guages have a release valve up by the guage. That is *not sufficient *and *does not take the place *of the valve at the tip.
> 
> This is the valve that you *MUST *have.



This needs to be a sticky in *BOLD* letters


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## blsnelling (Mar 19, 2009)

barneyrb said:


> This needs to be a sticky in *BOLD* letters



That's the whole idea. We've beat this topic into the ground so many times it isn't funny. It's time to put this thing to rest and help out a bunch of good folk while we're at it.


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## whitedogone (Mar 19, 2009)

blsnelling said:


> That's the whole idea. We've beat this topic into the ground so many times it isn't funny. It's time to put this thing to rest and help out a bunch of good folk while we're at it.



I'm sure Gary would approve :agree2:


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## 04ultra (Mar 19, 2009)

So *give us* a *brand name* and *part number*..






.


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## blsnelling (Mar 19, 2009)

I use a cheapy from AutoZone, forget the brand. It reads more accurately than the Lisle one I have.


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## 04ultra (Mar 19, 2009)

blsnelling said:


> I use a cheapy from AutoZone, forget the brand. It reads more accurately than the Lisle one I have.



This is not good with out a part number............Find out and get back to us...





.


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## rngrchad (Mar 19, 2009)

I use an uber expensive Mac Tools Gauge. I always wonder if it was worth the 157+ dollars off the tool truck...I wanted to buy an el cheapo schrader valve model from Harbor Freight, but my better judgement called up the local MacMan. 
Compression Tester "Bling" courtesy *MacTools. Brand: MacTools Part # is CT155*


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## blsnelling (Mar 19, 2009)

04ultra said:


> This is not good with out a part number............Find out and get back to us...
> 
> 
> 
> ...



There are many guages that will work. It's the valve at the tip that's most important.


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## WesternSaw (Mar 19, 2009)

*compression gauge*

Hello Brad
I think it is us newbies that are beating this to death.I know myself that before I go and purchase a tool I want to buy the RIGHT ONE.It is hard enough to find dollars sometimes for good tools,but to keep buying the wrong tools is even more expensive!Then there's the never ending,brand debate which for a newbie drives me crazy,you end up second guessing yourself,and don't buy anything.How about if you could post something like this.Taking quality and expense into account,that would end it for me
Thanks Lawrence

GOOD
BETTER
BEST


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## whitedogone (Mar 19, 2009)

Autozone= Actron CP7827

http://www.actron.com/product_detail.php?pid=16171

About $25


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## lovetheoutdoors (Mar 19, 2009)

i thought a compression tester without the valve would give you a high reading...at least thats what i have heard...mine has the schrader valve so i wouldnt know.


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## rngrchad (Mar 19, 2009)

lovetheoutdoors said:


> i thought a compression tester without the valve would give you a high reading...at least thats what i have heard...mine has the schrader valve so i wouldnt know.



Mine has all kinds of different connections, valves and other stuff I've never ever used and probably never will. Came in a nice plastic protective case too! I imagine the only tester more accurate than my Mac one might be the Snap-On, that is if they aren't made by the same company!


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## nmurph (Mar 19, 2009)

this is the gauge i bought from Autozone. it is an Actron.

someone (Brad) should also cover the proper way to test compression... i.e. throttle position and why it is important. engine temp, etc....


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## blsnelling (Mar 19, 2009)

whitedogone said:


> Autozone= Actron CP7827
> 
> http://www.actron.com/product_detail.php?pid=16171
> 
> About $25



That's the one I use. I have a more expensive Lisle and it does not work as well. It takes more pulls to pump it up and reads low to boot. Your mileage may vary.


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## blsnelling (Mar 19, 2009)

I usually test my engines cold. It's fine to test hot, but the reading will be 10-15 PSI lower. Yes, lower. Logically I would think it would be higher with thermal expansion, but that's not the case.

It's usually recommended to keep the throttle at WOT for a compression test so that the engine has no trouble drawing fresh air in. However, myself and others have found no difference in the readings. I do put the saw on fast idle when testing.


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## rngrchad (Mar 19, 2009)

blsnelling said:


> That's the one I use. I have a more expensive Lisle and it does not work as well. It takes more pulls to pump it up and reads low to boot. Your mileage may vary.



I think I'm gonna buy a bunch of different compression testers and use the one that reads the highest.


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## blsnelling (Mar 19, 2009)

Here's the ones I have. No, the Lisle doesn't read that low, lol. The Homey just has tons of compression.

Stihl MS210






Homelite SXL-925


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## lovetheoutdoors (Mar 19, 2009)

rngrchad said:


> I think I'm gonna buy a bunch of different compression testers and use the one that reads the highest.



it will make you feel better anyway wont it...


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## JJay03 (Mar 19, 2009)

I need to pick one of these up also the one I have now isnt too good.


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## FATGUY (Mar 19, 2009)

I have the same guage you do. Now, how do you know it's not reading high and the lisle is reading correctly?


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## blsnelling (Mar 19, 2009)

FATGUY said:


> Now, how do you know it's not reading high and the lisle is reading correctly?



Hit it with air from a compressor using a nozzle with a rubber tip. Try it on more than one compressor. In my case, the guage on my tank and the regulator match.


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## FATGUY (Mar 19, 2009)

that's a great idea, never thought of trying that


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## Biker Dude (Mar 19, 2009)

I have this one and it works just fine.





Snap-On makes it and the part # is EEPV03A 
I think it was around $250 off the truck but that was a few years ago.


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## 04ultra (Mar 19, 2009)

Brad ...Do you test your saws while there running ???







.


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## blsnelling (Mar 20, 2009)

04ultra said:


> Brad ...Do you test your saws while there running ???
> 
> 
> 
> ...



Why of course I do...........just not the compression


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## Bowtie (Mar 20, 2009)

04ultra said:


> Brad ...Do you test your saws while there running ???
> 
> 
> 
> ...


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## outdoorlivin247 (Mar 20, 2009)

I had a Star Products gauge that has a schader valve in the end of the hose that would not read more than 50lbs on any saw...It is sold by Snap-on and the reason I wanted to try it was b/c of price and the size of the hose...It was small and flexible enough to fit in the 041's which the Snap-on gauge I use at work would not fit in...So the schader valve at the end is not a tall tell sign...


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## BuddhaKat (Mar 20, 2009)

I read somewhere, (probably here), that compression testers with long hoses don't give an accurate reading because of the volume of compression within the hose itself. Apparently it's enough to throw off the reading.


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## Steve NW WI (Mar 20, 2009)

BuddhaKat said:


> I read somewhere, (probably here), that compression testers with long hoses don't give an accurate reading because of the volume of compression within the hose itself. Apparently it's enough to throw off the reading.



That my friend is the whole reason of this post. The schrader valve is a one way valve, which lets subsequent strokes build the pressure to the maximum the motor is capable of, and takes the variation of the amount of gas that needs to be compressed out of it.

BTW, I just got a cheapo (says IEC on the gauge face), $27 at Bumper to bumper, with a schrader valve and 3 or 4 adapters. I haven't tested it against a compressor yet, but seems close based on how hard different engines pull over.


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## 046 (Mar 20, 2009)

basic calibration says to use a known to be correct gauge. 
highest quality gauge I've got is a German made Drager. 

compression gauge is snap-on



FATGUY said:


> I have the same guage you do. Now, how do you know it's not reading high and the lisle is reading correctly?


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## MickJ (Mar 20, 2009)

Damn good topic.
Having said that before i got my gauge i did a search rather than asking a thrashed out question and fully understand the reasons for the correct valve placement.
Fwiw i got an ABW (probably only sold in oz - make a lot of mechanic tools) gauge, they are made in the US by "US gauge" which according to my research make the gauges for snap-on, but cost a lot more.
Funnily enough the super dear ABW gauge with all the fittings and plastic case has the valve where the quick release fitting for the hose extensions are and not at the tip, the cheaper one I picked only has 14 and 18mm fittings and no case - but has the valve at the tip!!


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## blsnelling (Mar 20, 2009)

outdoorlivin247 said:


> I had a Star Products gauge that has a schader valve in the end of the hose that would not read more than 50lbs on any saw...It is sold by Snap-on and the reason I wanted to try it was b/c of price and the size of the hose...It was small and flexible enough to fit in the 041's which the Snap-on gauge I use at work would not fit in...So the schader valve at the end is not a tall tell sign...



I don't know what the deal was with your guage, but it is a fact that you must have the Schrader valve at the tip. To indicate anything otherwise is to only mislead someone.


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## redunshee (Mar 20, 2009)

*compression tester*

Going to Autozone this AM. Curious to see how much differance between the Actron and one I got from Baileys.


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## blsnelling (Mar 20, 2009)

I'm going to ask Greg to chime in here. I've never seen the tester Baileys sells but am told that it does no have the required valve at the tip. Maybe Greg can clarify this for us. They're always looking to improve their product so it's only fair for him to know what the end users are experiencing.


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## almondgt (Mar 20, 2009)

Funny no one would mention the importance of a proper seal at the end you tap the hose fitting on the gauge into the cylinder head. I purchased a brand new KD compression tester and there is no seal of any kind on either of the fittings included in the kit. Tried an O ring still no good. Dismantled and Welded up a spark plug to fit on the testers hose still no good. Tested the KD on my compressor and it registered nearly the same. Just can't get the seal to the cylinder head. I am repeatedly using my fathers old HOLD THE SAW WITH ONE HAND..... HOLD THE GAUGE tightly to the cylinder head .....POSITION YOUR FOOT IN THE SAWS HANDLE PULL 3 OR 4 TIMES .......(IF COMPRESSION IS HIGH I NEED TO ALSO USE MY KNEE TO HOLD DOWN THE SAW) Provides what appears to be an accurate reading. Have done the compressor test on the old gauge and it does register nearly the same. I am leary of anyone providing compression test results over 160 pounds. Best I ever registered on my gauge was 150+/- lbs. :chainsawguy:


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## blsnelling (Mar 20, 2009)

almondgt said:


> Funny no one would mention the importance of a proper seal at the end you tap the hose fitting on the gauge into the cylinder head. I purchased a brand new KD compression tester and there is no seal of any kind on either of the fittings included in the kit. Tried an O ring still no good. Tried mounting a spark plug washer on the fitting still no good. I am repeatedly using my fathers old HOLD THE SAW WITH ONE HAND..... HOLD THE GAUGE tightly to the cylinder head .....POSITION YOUR FOOT IN THE SAWS HANDLE PULL 3 OR 4 TIMES .......(IF COMPRESSION IS HIGH I NEED TO ALSO USE MY KNEE TO HOLD DOWN THE SAW) Provides what appears to be an accurate reading. Have done the compressor test on the old gauge and it does register nearly the same. I am leary of anyone providing compression test results over 160 pounds. Best I ever registered on my gauge was 150+/- lbs. :chainsawguy:



Never been an issue. Both of my guages have o-rings seals at the end. Are you using a guage that threads into the head or one of the push on types?

Why do you have a problem believe readings over 160 PSI? I've got several, one at 200. I've got some that are under 150.


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## redunshee (Mar 20, 2009)

blsnelling said:


> I'm going to ask Greg to chime in here. I've never seen the tester Baileys sells but am told that it does no have the required valve at the tip. Maybe Greg can clarify this for us. They're always looking to improve their product so it's only fair for him to know what the end users are experiencing.



Called Baileys and they said it was at the tip. Apparently its inside about 1/2 in. so its hard to see w/o shining a light in opening. Kinda thought my Baileys was somewhat accurate but know I know


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## blsnelling (Mar 20, 2009)

redunshee said:


> Called Baileys and they said it was at the tip. Apparently its inside about 1/2 in. so its hard to see w/o shining a light in opening. Kinda thought my Baileys was somewhat accurate but know I know



Good deal. I just couldn't imagine them selling the wrong kind of guage as their only option. Puts that old myth to rest.


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## almondgt (Mar 20, 2009)

The KD tester utilizes a rubber hose and threads into the cylinder head and has been useless to me to date. Both of my testers utilize the Schrader tips. I trust the gauge that works for me and have tested approximately 30 saws, tired, saws, newly rebuilt saws, saws that I rebuilt and have run in the bush for extended periods of time and new saws. To my knowledge all the saws are stock. None have registered over 155 PSI. I did change seals in an Echo 500vl recently. I tested the saw prior to disassembly and it was 150 PSI on the money. I damaged the base gasket so I cut several of my own with the material I had on hand. The best reading I get now is 135. I will leave the 500vl at such until I find an OEM gasket to fit. Just my personal experience on the subject. I would be interested in further observations regarding same.:greenchainsaw:


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## blsnelling (Mar 20, 2009)

Most saws are closer to 150-160 PSI, but not all. Go test a new Dolmar 420...190 PSI stock. Or test a old Homey SXL-925. You'll likely pull 180 PSI. Mine's 200 without a base gasket. Many of my modded saws are in the 170-175 PSI range. My Stihl S-10 has new rings and a good cylinder but still only makes 125 PSI.


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## litefoot (Mar 20, 2009)

Brad,
Here's a quote from an earlier post you made about the Lisle:



blsnelling said:


> I just got the Lisle 20250 I ordered from Amazon. I chose the free shipping and got it in like 2 days. I took my modded MS260 and checked it a couple times with my AutoZone guage I've been using. I then checked it a couple times with the new Lisle. Both guages read with in 2 lbs of each other at 178-180 pounds. It cost me $27, but I know I'm getting a good reading now.



Now you're saying this:



blsnelling said:


> That's the one I use. I have a more expensive Lisle and it does not work as well. It takes more pulls to pump it up and reads low to boot. Your mileage may vary.



When did your Lisle lose its accuracy? I bought the 20250 based, in part, on your earlier recommendation.


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## almondgt (Mar 20, 2009)

litefoot said:


> Brad,
> Here's a quote from an earlier post you made about the Lisle:
> 
> 
> ...



Always considered a Lisle gauge to be a good one, not sure now. I'll stick with the gauge I have. Hold em down tight and pull with a vengeance.


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## blsnelling (Mar 20, 2009)

almondgt said:


> Always considered a Lisle gauge to be a good one, not sure now.



It's probably a good tool, but I just didn't find it to work as well as others on these little chainsaw engines.


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## Grande Dog (Mar 20, 2009)

redunshee said:


> Called Baileys and they said it was at the tip. Apparently its inside about 1/2 in. so its hard to see w/o shining a light in opening. Kinda thought my Baileys was somewhat accurate but know I know



Howdy,
I'm not sure who told you that or why but, ours is on the gauge. The gauge we sell is the same one Husqvarna sells to the dealers. We just access it directly from the manufacturer in Taiwan. We used them for many years without worry. I can't vouch for accuracy because that was the only one we used. 

Brad,
If you want to do some comparison testing, I'll send you one. 
Regards
Gregg


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## blsnelling (Mar 20, 2009)

Grande Dog said:


> Howdy,
> I'm not sure who told you that or why but, ours is on the gauge. The gauge we sell is the same one Husqvarna sells to the dealers. We just access it directly from the manufacturer in Taiwan. We used them for many years without worry. I can't vouch for accuracy because that was the only one we used.
> 
> Brad,
> ...



Thanks for the reply Gregg. I'd be more than happy to test my AutoZone and Lisle guages with the guage you're selling. I can test them against the guages on my air compressor and regulator, as well as on the same saw.


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## JJay03 (Mar 20, 2009)

blsnelling said:


> Most saws are closer to 150-160 PSI, but not all. Go test a new Dolmar 420...190 PSI stock. Or test a old Homey SXL-925. You'll likely pull 180 PSI. Mine's 200 without a base gasket. Many of my modded saws are in the 170-175 PSI range. My Stihl S-10 has new rings and a good cylinder but still only makes 125 PSI.



I guess some of the older saw had a higher compression ratio? Same with the modded saw prob raised the compression.


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## joe25DA (Mar 20, 2009)

I have a harbor freight one, generally I wouldnt buy my tools from them, but the price was right, and its built pretty well.


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## blsnelling (Mar 20, 2009)

JJay03 said:


> I guess some of the older saw had a higher compression ratio? Same with the modded saw prob raised the compression.



That is correct. The new Dolmars, or at least the 420, have higher compression than any other new saw I've seen. That's how they make the crazy torque they do.


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## outdoorlivin247 (Mar 20, 2009)

almondgt said:


> The KD tester utilizes a rubber hose and threads into the cylinder head and has been useless to me to date. Both of my testers utilize the Schrader tips. I trust the gauge that works for me and have tested approximately 30 saws, tired, saws, newly rebuilt saws, saws that I rebuilt and have run in the bush for extended periods of time and new saws. To my knowledge all the saws are stock. None have registered over 155 PSI. I did change seals in an Echo 500vl recently. I tested the saw prior to disassembly and it was 150 PSI on the money. I damaged the base gasket so I cut several of my own with the material I had on hand. The best reading I get now is 135. I will leave the 500vl at such until I find an OEM gasket to fit. Just my personal experience on the subject. I would be interested in further observations regarding same.:greenchainsaw:



You might want to check out this recall...

echo recall
http://www.cpsc.gov/cpscpub/prerel/prhtml86/86053.html


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## Grande Dog (Mar 20, 2009)

blsnelling said:


> Thanks for the reply Gregg. I'd be more than happy to test my AutoZone and Lisle guages with the guage you're selling. I can test them against the guages on my air compressor and regulator, as well as on the same saw.



Howdy,
It's on the way.
Regards
Gregg


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## blsnelling (Mar 20, 2009)

Grande Dog said:


> Howdy,
> It's on the way.
> Regards
> Gregg



I'll be sure to update this thread. Thanks again for your great service to this forum.


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## almondgt (Mar 20, 2009)

Grande Dog said:


> Howdy,
> It's on the way.
> Regards
> Gregg



 You guys should post in private messages. Freebies make my mouth water and my knees shake. I bet blsnelling had this one figured out before Grande Dog even offered. Sly cat!


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## blsnelling (Mar 20, 2009)

almondgt said:


> You guys should post in private messages. Freebies make my mouth water and my knees shake. I bet blsnelling had this one figured out before Grande Dog even offered. Sly cat!



No, but it doesn't surprise me. I've already got two guages. Gregg's just that interested in good customer service. You can't go wrong buying from Baileys!


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## Grande Dog (Mar 20, 2009)

blsnelling said:


> I'll be sure to update this thread. Thanks again for your great service to this forum.


Howdy,
Since we were doing this, I had the warehouse check it. Looks like I'm all wet. They changed it to where the valve is in the end of the hose and the release is in the gauge. It's still on the way. I would still like a comparison, and I think other folks would be interested also. Sorry for the misinformation.
Regards
Gregg


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## outdoorlivin247 (Mar 20, 2009)

blsnelling said:


> No, but it doesn't surprise me. I've already got two guages. Gregg's just that interested in good customer service. You can't go wrong buying from Baileys!



I love the marketing end of it...Willing to put it in someones hand that will get back w/ him...I hope he sells 100+ for doing it...


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## almondgt (Mar 20, 2009)

Now the free promotion/ advertising. You guys have no [email protected] all


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## Airecon (Mar 20, 2009)

Somone said you need to make this post a sticky. If you get too many sticky's I think it clutters up the first page. I'd rather click on the site and see post and pics of saws not all sticky's. What should of happened a long time ago is there needs to be one sticky, then within that sticky have links to other threads about chainsaw repair, tips for certain models and maybe mods . Each thread should be written by well respected, knowledgeable members of the forum- you don't want any ole yahoo like me writing the thread. Then maybe the writer could pass it along to some other "key" members and let them proof read it and suggest other ideas. When they have the final copy, post it up and lock the thread. This way you have a well written, thread with good pics that's planned and informative without a lot of nonsense post. Some "key" members have made 1000's of post and already spent more time answering stupid questions.

The info is already out there in the forum, but sometimes its not very well written and organized and its cluttered up with nonsense post.


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## KMB (Mar 20, 2009)

joe25DA said:


> I have a harbor freight one, generally I wouldnt buy my tools from them, but the price was right, and its built pretty well.



I don't want to cause you grief, but I have the Harbor Freight version and it quit on me the other day. It will not hold compression. I think I've had it for about 2 or 3 years. I'll be getting the Actron from AutoZone soon.

Kevin


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## blsnelling (Mar 20, 2009)

KMB said:


> I don't want to cause you grief, but I have the Harbor Freight version and it quit on me the other day. It will not hold compression. I think I've had it for about 2 or 3 years. I'll be getting the Actron from AutoZone soon.
> 
> Kevin



I bet your Schrader valve just needs tightened. I have mine.


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## blsnelling (Mar 20, 2009)

Grande Dog said:


> Howdy,
> Since we were doing this, I had the warehouse check it. Looks like I'm all wet. They changed it to where the valve is in the end of the hose and the release is in the gauge. It's still on the way. I would still like a comparison, and I think other folks would be interested also. Sorry for the misinformation.
> Regards
> Gregg



LOL See there, they already upgraded the product. You might want to update the desription to say so. It still says it only has the one valve.


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## KMB (Mar 20, 2009)

blsnelling said:


> I bet your Schrader valve just needs tightened. I have mine.



Now why didn't I think of that.... I just bought the necessary valve tool for my vehicle tires, so it's worth a try. Thanks.

Kevin


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## redunshee (Mar 20, 2009)

Grande Dog said:


> Howdy,
> Since we were doing this, I had the warehouse check it. Looks like I'm all wet. They changed it to where the valve is in the end of the hose and the release is in the gauge. It's still on the way. I would still like a comparison, and I think other folks would be interested also. Sorry for the misinformation.
> Regards
> Gregg



Now I don't know if my Baileys tester has the Schraeder valve in the tip or not. Do I understand you to say the "new" ones have the valve in the tip? Any idea when they changed designs? The one I purchased about 1 yr. ago has the same model# as the current model(G-320HD) .


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## woodguy105 (Mar 20, 2009)

blsnelling said:


> This topic comes up every week and often more frequently. You absolutely *MUST *have a Schrader valve at the tip of your compression guage for use on a small 2-stroke engine. If it does not, you *cannot *use it, period. A Schrader valve is what's found in the stem of your car rims. The reason it is required is because of the small volume of these engines. It is not enough to pump up the pressure of the hose with every pull and you will end up with a way low reading. I wonder how many engines have been torn down that were perfectly fine? Some guages have a release valve up by the guage. That is *not sufficient *and *does not take the place *of the valve at the tip.
> 
> Good Idea Brad...maybe a stickey double header Compression tester / Tach thread is in order.


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## woodguy105 (Mar 20, 2009)

redunshee said:


> Now I don't know if my Baileys tester has the Schraeder valve in the tip or not. Do I understand you to say the "new" ones have the valve in the tip? Any idea when they changed designs? The one I purchased about 1 yr. ago has the same model# as the current model(G-320HD) .



I got one for xmas from Baileys and the valve was not on the fitting end as is needed..ended up sending it back...looks like it might be time to reorder!


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## whitedogone (Mar 20, 2009)

Do we really need another thread (65 posts and counting) to tell everybody to go to Autozone and buy a compression gauge?


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## rngrchad (Mar 20, 2009)

046 said:


> basic calibration says to use a known to be correct gauge.
> highest quality gauge I've got is a German made Drager.
> 
> compression gauge is snap-on



And that my friends, is the gauge all gauges should be compared to. Snap-On. If I ever care enough about compression readings on a work saw, I think I'll go back to the dealership I worked at and compare my Mac Gauge to the heavy r+r technician's Snap On one. And yes, if I didn't own a Snapon Gauge, it would probably take over 65 posts to convince me to spend 250 bucks rather than 15 for one from Autozone


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## cpr (Mar 20, 2009)

blsnelling said:


> Here's the ones I have. No, the Lisle doesn't read that low, lol. The Homey just has tons of compression.
> 
> Stihl MS210
> 
> ...


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## 046 (Mar 20, 2009)

here's part of my instrument drawer. 

two Snap-on compression gauge sets. one for lower range to 250 psi, other for higher pressures. all sorts of adapters for myriad of plug sizes out there. all adapters have shrader valve at tip. 

Drager Gauge has been old faithful... had that Drager though thick and thin. 
other gauge is for fuel injection to 100 psi. Snapon oil pressure, fuel pressure/vacuum gauges are inside red cases.


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## whitedogone (Mar 20, 2009)

I have a freind that is a chevy wrench. I told him I wanted to check my cheap as gauge with his Snapon gauge. He brought home his and a buddies MAC. He had made a manifold that all 3 screwed into. We hooked them all up and used my compressor to pressurize the whole afair. They all showed within 2psi @40#, 3 [email protected]#, and at 120 they were all back to within 2# of each other. At 140 they were within 4psi of each other. My compressor wouldn't go any higher than that. WDO


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## 046 (Mar 20, 2009)

most gauges are well within accuracy range.... if they are properly calibrated by checking against a known to be correct gauge. 

Lisle seems to make consistently high quality specialty tools. 



whitedogone said:


> I have a freind that is a chevy wrench. I told him I wanted to check my cheap as gauge with his Snapon gauge. He brought home his and a buddies MAC. He had made a manifold that all 3 screwed into. We hooked them all up and used my compressor to pressurize the whole afair. They all showed within 2psi @40#, 3 [email protected]#, and at 120 they were all back to within 2# of each other. At 140 they were within 4psi of each other. My compressor wouldn't go any higher than that. WDO


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## KMB (Mar 23, 2009)

blsnelling said:


> I bet your Schrader valve just needs tightened. I have mine.





KMB said:


> Now why didn't I think of that.... I just bought the necessary valve tool for my vehicle tires, so it's worth a try. Thanks.
> 
> Kevin



The Schrader valve was loose, so I tightened it down 'just snug', but it still doesn't work. Actually, it wouldn't read at all after that. With it 'just snug', the valve doesn't work like it should (the valve end piece will not move up/down). With the valve loosened, it will function (I can push the valve end piece and it moves up/down). I'm not sure if I'm describing this properly. I think I just need to get a new one and compare how the Schrader valve's

Kevin


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## davido30093 (Mar 23, 2009)

*Replace the stem*

Remove the valve stem completely and get a new one. Most autoparts stores have them. That should fix your guage.


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## blsnelling (Mar 23, 2009)

davido30093 said:


> Remove the valve stem completely and get a new one. Most autoparts stores have them. That should fix your guage.



I think they may be a special valve with a very weak spring. I'm not sure on that.


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## Haywire Haywood (Mar 23, 2009)

Grande Dog said:


> Howdy,
> Since we were doing this, I had the warehouse check it. Looks like I'm all wet. They changed it to where the valve is in the end of the hose and the release is in the gauge. It's still on the way. I would still like a comparison, and I think other folks would be interested also. Sorry for the misinformation.
> Regards
> Gregg



I walked out to the barn and had a look at my Bailey's gauge that I just bought but haven't used yet. It doesn't have the screw in tire valve as is traditional, it's permanently made into the tip instead. It replaced my old Advance Auto gauge that had a QD for different hose fittings. It was cheap and got to where when I would pull on the start cord, the gauge would pop off at the QD. Impossible to use.

Didn't think Bailey's would sell something not suited to the purpose and I wasn't disappointed. 

Ian


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## blsnelling (Mar 23, 2009)

Check out Greggs response. It didn't used to have the valve but was updated earlier this year.


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## Haywire Haywood (Mar 23, 2009)

Glad I waited till now to get it then... LOL

Ian


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## KMB (Mar 23, 2009)

davido30093 said:


> Remove the valve stem completely and get a new one. Most autoparts stores have them. That should fix your guage.





blsnelling said:


> I think they may be a special valve with a very weak spring. I'm not sure on that.



I'll take the valve out and take it to a local auto parts store and see what they have and compare.

Kevin


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## 046 (Mar 23, 2009)

highly unlikely you will find the right one without buying a new gauge. 
I'd call the Snap-on dealer... valve from any snapon adapter will work. 

the parts store is worth a try too



KMB said:


> I'll take the valve out and take it to a local auto parts store and see what they have and compare.
> 
> Kevin


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## KMB (Mar 23, 2009)

blsnelling said:


> I think they may be a special valve with a very weak spring. I'm not sure on that.





046 said:


> highly unlikely you will find the right one without buying a new gauge.
> I'd call the Snap-on dealer... valve from any snapon adapter will work.
> 
> the parts store is worth a try too



Brad was right. I went to the local auto parts store and they had a valve with a stronger spring. For a $1.30 I gave it a try. The gauge read a max of about 90psi on my 970 and I know it has more than that. When the tester was working properly with the original valve (before it broke), the 970 was reading around 150psi (I didn't record it...should have...and will). So a new tester it will be.

Kevin


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## outdoorlivin247 (Mar 23, 2009)

046 said:


> highly unlikely you will find the right one without buying a new gauge.
> I'd call the Snap-on dealer... valve from any snapon adapter will work.
> 
> the parts store is worth a try too



I know that Snap-on has them b/c a guy I work w/ just replaced his in the one I borrrow...


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## KMB (Mar 23, 2009)

outdoorlivin247 said:


> I know that Snap-on has them b/c a guy I work w/ just replaced his in the one I borrrow...



Well...with 2 posts about Snap-on, I'll have to see if I can find where a Snap-on dealer is locally here in the boonies. I guess the phone book is a good place to start...

Kevin


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## gatkeper1 (Mar 23, 2009)

KMB said:


> Well...with 2 posts about Snap-on, I'll have to see if I can find where a Snap-on dealer is locally here in the boonies. I guess the phone book is a good place to start...
> 
> Kevin


Snap-on will sell it to you online for a mere 249.99


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## KMB (Mar 23, 2009)

gatkeper1 said:


> Snap-on will sell it to you online for a mere 249.99



For the valve???? :jawdrop:

Kevin


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## 046 (Mar 23, 2009)

snap-on may be high, but they are real good about support. 
they should have the tiny valve separately. 

as brad said... it's a special low spring tension shrader valve. 
one of my snap-on adapters was not holding, so I took the shrader valve out and tossed it.... mistake.... though it was a regular shrader valve, which I had loads of. after finding out a std valve wouldn't work... was digging in the trash until I found the old valve. 

turned out main seal was not holding. twisted a bit harder and adapter held fine with old valve tip.


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## KMB (Mar 23, 2009)

I just emailed Snap-on to see if they would quote me a price for mailing me a shrader valve...or point me to where the closet Snap-on truck is. I did mention that it wasn't for a Snap-on compression tester. I'll see if they reply.

BTW Brad...didn't mean to hijack your thread...

Kevin


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## 046 (Mar 23, 2009)

don't tell them it's not for a snap-on tool. why in the world would they want to support someone else's $40 gauge. vs snap-on's for $250

ask a shrader valve that fits an adapter from a two piece snapon gauge set. look at pictures posted above. 

a tiny valve is customer service only. what you need to do is find who the snap-on dealer that does the route near your house. 

you can call local garages nearby or snapon HQ.


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## KMB (Mar 23, 2009)

046 said:


> don't tell them it's not for a snap-on tool. why in the world would they want to support someone else's $40 gauge. vs snap-on's for $250
> 
> ask a shrader valve that fits an adapter from a two piece snapon gauge set. look at pictures posted above.
> 
> ...



I didn't think it would matter if I wanted to buy the part...not have it given to me as support for their product. But you could be right in that they don't want to be bothered. If that's the case, they won't reply to my email I sent.

I'll try to find the local Snap-on guy.

Kevin


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## gatkeper1 (Mar 23, 2009)

KMB said:


> For the valve???? :jawdrop:
> 
> Kevin


Well it is Snap-On after all.
Actually i thought you wanted the complete set. Heres a link to the valve
http://buy1.snapon.com/catalog/sear...nsfr=true&search_type=Part&store=snapon-store


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## KMB (Mar 23, 2009)

gatkeper1 said:


> Well it is Snap-On after all.
> Actually i thought you wanted the complete set. Heres a link to the valve
> http://buy1.snapon.com/catalog/sear...nsfr=true&search_type=Part&store=snapon-store



Thanks for the link. Hopefully the shipping won't scare me off.... At least now I have a part number.

Kevin


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## blsnelling (Mar 25, 2009)

I just got the guage from Baileys. It's the middle of the work day so I don't have time for a full report right now. However, I did throw it on the 029 Super that was pulling 135-138 on my AutoZone guage. This guage from Baileys pulls 142-143 PSI. I'm liking it already, lol. I don't care if it's accurate, I just want it to read high:greenchainsaw:. I'm curious to see the difference in how they read pressurized by a compressor tank vs how the read on the same saw. BTW, there is a one-way valve about 1/2" up in the tip. It is not a removeable Schrader valve, but it does have the required one-way valve.


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## stipes (Mar 25, 2009)

blsnelling said:


> I just got the guage from Baileys. It's the middle of the work day so I don't have time for a full report right now. However, I did throw it on the 029 Super that was pulling 135-138 on my AutoZone guage. This guage from Baileys pulls 142-143 PSI. I'm liking it already, lol. I don't care if it's accurate, I just want it to read high:greenchainsaw:. I'm curious to see the difference in how they read pressurized by a compressor tank vs how the read on the same saw. BTW, there is a one-way valve about 1/2" up in the tip. It is not a removeable Schrader valve, but it does have the required one-way valve.



Brad,,,if she runs good,,idles good starts good,,run the hell outta it!!!! P.S. Amazing work you did on that,,I had to say again...So hard to believe thats the same saw!!!!


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## Motodeficient (Mar 30, 2009)

I have never used a compression gauge before, but I want to buy one. If I buy one with the schrader valve for use in a small 2-stroke engine like a chainsaw, will the same gauge also work for larger 2-stroke engines like a dirtbike or snowmobile?


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## 046 (Mar 30, 2009)

yes.. providing what you are measuring has right spark plug type/size



Motodeficient said:


> I have never used a compression gauge before, but I want to buy one. If I buy one with the schrader valve for use in a small 2-stroke engine like a chainsaw, will the same gauge also work for larger 2-stroke engines like a dirtbike or snowmobile?


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## nmurph (Mar 30, 2009)

brad,
did you ever evaluate the gauges to see which is more accurate?


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## Evanrude (Mar 30, 2009)

To ease everyone on the accuracy of the Lisle, mine is right on with two separate air gauges/compressors. Maybe Brad got one that was produced on Friday.


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## KMB (Apr 7, 2009)

KMB said:


> I don't want to cause you grief, but I have the Harbor Freight version and it quit on me the other day. It will not hold compression. I think I've had it for about 2 or 3 years. I'll be getting the Actron from AutoZone soon.
> 
> Kevin





blsnelling said:


> I bet your Schrader valve just needs tightened. I have mine.





KMB said:


> The Schrader valve was loose, so I tightened it down 'just snug', but it still doesn't work. Actually, it wouldn't read at all after that. With it 'just snug', the valve doesn't work like it should (the valve end piece will not move up/down). With the valve loosened, it will function (I can push the valve end piece and it moves up/down). I'm not sure if I'm describing this properly. I think I just need to get a new one and compare how the Schrader valve's
> 
> Kevin





gatkeper1 said:


> Well it is Snap-On after all.
> Actually i thought you wanted the complete set. Heres a link to the valve
> http://buy1.snapon.com/catalog/sear...nsfr=true&search_type=Part&store=snapon-store





KMB said:


> Thanks for the link. Hopefully the shipping won't scare me off.... At least now I have a part number.
> 
> Kevin



Thought I'd bump this thread. This might help someone for reference. I used the link from gatkeeper1 and ordered a valve ($2.17 to my door, UPS). It fits in my non-SnapOn tester and works just fine. 

Kevin


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## Evan (Apr 7, 2009)

id guess 85-90 % of testers in cadders hands are shcrader vavle.

i honestly havent seen the other style in shops or garages maybe 90 percent are shcaders

i bet the other style costs more


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## blsnelling (Apr 7, 2009)

I have not had a chance to do any more definitive testing. I did use both guages on another saw and got within a couple pounds of each other. * I give a thumbs up to the Baileys guage!*


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## 046 (Apr 7, 2009)

the only way to know for sure which gauge is accurate is to compare against a calibration standards gauge. 

since most folks don't have one of those and will not pay the costs to send out for calibration. 

the next best thing is to compare against the highest quality gauges commercially available. which is Drager and Snap-on. both of those are calibrated at the factory. yes there is a reason the best costs more. 



nmurph said:


> brad,
> did you ever evaluate the gauges to see which is more accurate?


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## briantutt (Apr 15, 2009)

At the risk of sounding like an idiot....

Are compression testers just a gauge with check valve on the inlet to trap pressure? and an outlet valve to vent it off when done?

and if these are just bourdon tube gauges you can't expect better than 3% plus or minus and usually 5% plus or minus for accuracy and that is full scale range so if it's a 300 psig gauge it could be off as much as 15 psig for any reading and still pass the spec at the manufacturer. I spec this type of gauge in all the time and at the prices they sell these testers for there is no way they are better than 3% and are more than likely th 5% variety. In any case they should repeat the reading so if you figure out it's 5 psig off from a calibrated reading it should stay 5 psig off unless it's abused.


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## deezle_dog (Apr 15, 2009)

briantutt said:


> At the risk of sounding like an idiot....
> 
> Are compression testers just a gauge with check valve on the inlet to trap pressure? and an outlet valve to vent it off when done?




That is correct.


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## stihlbro (Apr 15, 2009)

Reading here and thought I would add my two cents here. I have a snap-on compression tester and two others that where alot cheaper. All three read really close to each other. But my thoughts on comression here is it only makes you scratch your head and stay up at night. Checking compression on a stock saw for reference the guages are helpful. Most of the time you can tell if compresion is good by the pull of the starter rope. To me a good cutting saw the compression is a given. Now........trying to get 200 psi compression on a 026 like everyone else says is so easy......Well let me tell you I personally have failed with every possible scenario possible. With that said I have checked the same saw numerous times cold, hot, sitting for awhile and get different readings everytime. So all in all my opinion of compression readings can be misleading. Altitude? Ambient temperature? Hot? Cold? Your guage? My guage? I will agree with 046 on calibrating a guage for accuracy. And you must have a schrader valve....sometimes a valve stem valve will work. Keep pulling until the guage maxes out. Hopefully I am not the only one experiencing this.


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## Jtheo (May 2, 2009)

blsnelling said:


> I'm going to ask Greg to chime in here. I've never seen the tester Baileys sells but am told that it does no have the required valve at the tip. Maybe Greg can clarify this for us. They're always looking to improve their product so it's only fair for him to know what the end users are experiencing.




I bought the compression tester from Bailey's and it does Not have the Schrader valve at the tip.


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## Haywire Haywood (May 2, 2009)

When did you buy it? If recently, it doesn't look like a typical schrader valve, just looks like a brass blockage up in there.

Ian


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## blsnelling (May 2, 2009)

You are correct that it does not have a "Schrader" valve. However, it does hava a one way valve right at the tip of the hose. It will work fine.


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## Jtheo (May 2, 2009)

Haywire Haywood said:


> When did you buy it? If recently, it doesn't look like a typical schrader valve, just looks like a brass blockage up in there.
> 
> Ian



I bought it last summer. I looked in the end of the connecting hose and it looks just like you said. 

So this should do the job. Right?

Thing is, I just ordered one from AutoZone a little while ago, so I guess I can compare the two. If I can find out out to do the test properly. :greenchainsaw:


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## blsnelling (May 2, 2009)

I don't know when they made the switch. What kind of compression readings do you get from it? If it's reading 140-160 PSI, it has a valve at the tip. Otherwise, your readings would be much lower.


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## derekc (May 15, 2009)

*Back to how dry the inside should be for accurate test.*

Back to how dry the inside should be for accurate test.
100% dry and well-lubricated with 2-stroke oil on the rings make a big difference. 
I just put together a 026 with new ring, piston and reused the cylinder. 100% dry is 140 PSI. When I squeezed some oil into the plug hole, pull it a few rounds for the oil to go in, then PSI is 180.
So, how dry should it be? Run the saw for 5 minutes first, cool it down, then test again?


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## husqvarmit (May 15, 2009)

got mine from echo for 12 dollors and works right everytime


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## Haywire Haywood (May 15, 2009)

derekc said:


> Back to how dry the inside should be for accurate test.
> 100% dry and well-lubricated with 2-stroke oil on the rings make a big difference.
> I just put together a 026 with new ring, piston and reused the cylinder. 100% dry is 140 PSI. When I squeezed some oil into the plug hole, pull it a few rounds for the oil to go in, then PSI is 180.
> So, how dry should it be? Run the saw for 5 minutes first, cool it down, then test again?



Dry... if you want to see the compression go up, squirt a little bar oil in there. Don't ask me how I know this. This also works quite well for mosquito fogging.

Ian


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## derekc (May 15, 2009)

I know.
And during the assembling, the rings are supposed to be lubricated before they go into the cylinder. How much lubrication it has will have effect on the compression test result.
Best to test is then after running the saw for say 5 mins and cooling it down?


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## Haywire Haywood (May 15, 2009)

I'd say start it and run just until it stops smoking excessively. Shouldn't take but 30 seconds or a minute at most.

Ian


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## flashpuppy (May 15, 2009)

rngrchad said:


> I imagine the only tester more accurate than my Mac one might be the Snap-On, that is if they aren't made by the same company!



It's all made in Taiwan. Don't worry. My new Mac sockets I ordered (I was missing two of them from a set) cost me $32 and had a "Made in Taiwan" sticker right on the bag....


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## 7oaks (May 16, 2009)

blsnelling said:


> My Stihl S-10 has new rings and a good cylinder but still only makes 125 PSI.



Brad...

Just caught this quote and it makes me feel much better as my S-10, 08 and 08s as well as my Contra all register 130 psi on my Lisle guage. My more modern saws all read 150 on the same guage. I was thinking I would have to rebuild the older saws even though the pistons, rings and cylinders all look pretty damn good.

Thanks tons for this observation. I am much relieved. My little bit of rep coming your way.

 ...Carl


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## rngrchad (May 18, 2009)

flashpuppy said:


> It's all made in Taiwan. Don't worry. My new Mac sockets I ordered (I was missing two of them from a set) cost me $32 and had a "Made in Taiwan" sticker right on the bag....



Yeh you must have bought the Mac "Edge" sockets. Those I'm thinking are their low-end tools designed to compete with Snap' On's Blue Point stuff. I've wrenched alot with those "edge" sockets by Mac. They seem fine. Nothing special...but seem to work as well as my Flank drive Snap on Sockets...but they are a bit bulkier than my Snap On Flank Drive sockets...anywho on with the thread.


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## MS260 Fan (May 22, 2009)

*Pulls to get max compression?*

Everyone's talking about compression values. Just wondering in your experience how many pulls it usually take to get the compression max out on the schrader style gages. I've seen gains up to the 10th pull on some of my saws. 

Also, may be operator error but checked my 034 one day cold and it was 130 and 2 weeks later it was 145. I'll check it again in 2 weeks. I've got my fingers crossed for 155.


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## blsnelling (May 23, 2009)

7oaks said:


> Brad...
> 
> Just caught this quote and it makes me feel much better as my S-10, 08 and 08s as well as my Contra all register 130 psi on my Lisle guage. My more modern saws all read 150 on the same guage. I was thinking I would have to rebuild the older saws even though the pistons, rings and cylinders all look pretty damn good.
> 
> ...



Glad I could save you the trouble


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## HittinSteel (Jun 9, 2009)

Grande Dog said:


> Howdy,
> I'm not sure who told you that or why but, ours is on the gauge. The gauge we sell is the same one Husqvarna sells to the dealers. We just access it directly from the manufacturer in Taiwan. We used them for many years without worry. I can't vouch for accuracy because that was the only one we used.
> 
> Brad,
> ...



Gregg, I think some of the confusion (at least on my part) was from the first question under the FAQ section. http://www.baileysonline.com/itemdetail.asp?item=G+320HD&catID=
May want to edit the answer as to describe how this tester works. Would hate to see people shopping based on the word shrader pass the gauge by.


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## Grande Dog (Jun 9, 2009)

Howdy,
Thanks for the heads up. I had it changed.
Regards
Gregg


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## blsnelling (Jun 9, 2009)

Just for a follow up. My guage is still working perfectly and is my go-to guage now.


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