Compression

[ktoom]

Im doing a compression check on my old 044. I tested it and got 140 PSI, but it feels more like 160 PSI. Then i did it with my new MS 440 and only got 160 PSI. Now the hose on the compression tester is a foot long. Is that why my readings are so off? I think i need to go get a different/ smaller hose compression tester. Sears has one with all the different hose lengths. What do you guys think?

 

[fishhuntcutwood]

You need to have the right kind of tester. The one with the Schrader valve at the end of the hose from what I understand.

How much compression are you after? These numbers are fine. 160 is about right for a new saw. I mentioned the other day that I think your 140 on your other saw doesn't quite warrent a rebuild yet.

 

[ktoom]

Yes, i agree. When im pulling it over slowly it almost pulls the saw outta my hand. What i did to he saw was i put a newer cylinder on it and it seemed to help alot.

 

[ktoom]

How much play in the crank is acceptable? Ive got a little bit.

 

[Tree Sling'r]

Never tested compression on anything of mine. Where do you guys find a good tester - for future reference.

 

[fishhuntcutwood]

Yes, i agree. When im pulling it over slowly it almost pulls the saw outta my hand. What i did to he saw was i put a newer cylinder on it and it seemed to help alot.

Yeah, but you said, "only 160" and you're asking about why your readings are so far off. I think they're probably accurate, and where they should be.

 

[Lakeside53]

Doesn't seem like you have a problem with your compression tester at all.

 

[fishhuntcutwood]

Andy, was I right about the Schrader valve being at the end of the hose? That's the kind you want right?

 

[Lakeside53]

How much play in the crank is acceptable? Ive got a little bit.

If your talking about the flywheel or clutch end, the answer is zero. If you are talking about the side to side on the rod, there is alway some, but zero "up and down".

 

[Lakeside53]

Andy, was I right about the Schrader valve being at the end of the hose? That's the kind you want right?

Right.. but those numbers indicate he probably has the correct type.

 

[RiverRat2]

Right.. but those numbers indicate he probably has the correct type.

Andy, The shrader valve is in the end that screws into the sparkplug hole??? can you post a pic or give a brand name or model # please sir????

 

[Lakeside53]

Andy, The shrader valve is in the end that screws into the sparkplug hole??? can you post a pic or give a brand name or model # please sir????

Yep...

tomorrow...

...and brand? heck., I don't know - bought mine at the local auto parts store....

 

[RaisedByWolves]

Heres a pic ofthe shrader in the end of the hose that screws into the plug hole. This one has different adapters on the hose for different thread sizes.

The schrader in the very end of the hose is essential, but Heres another good feature.



On the other end of the hose, rather than having the guage attached directly to the hose some of the better ones will have a quick connect fitting.

Makes it much easier to thread the adapter into the plug hole without the guage on it.

As for the brand? $2 flea market brand.



But I think its a snap on.

 

[Lakeside53]

yep....

Also, best NOT to use any adapters, particularly on small saws. Even a couple of CC can make a big error in readings. Mine screws into the plug without adapters, but I can put adapters on for other sizes.

 

[RaisedByWolves]

Agreed.




That one there has the adapter on it, but Ive seen some that are huge.



I dont get the idea of the spark plug sized ones.