# echo pb-500 backpack blower bogs at full throttle



## JONSSTIHL (Sep 15, 2014)

My leaf blower has started giving me trouble lately. It slows down at full throttle 


It runs fine until it gets warm, maybe 5-10 minutes then it starts slowing down at full throttle every once in a while until it gets progressively worst and eventually I can't get it to run at full throttle. I can keep it running by letting off the throttle for a few seconds then returning to wot. the problem is intermitent so I can get the job done it just takes longer. 


I checked the screen in the exhaust but it wasn't very dirty. I also took the carb off and sprayed it down with carb cleaner. found out it is a strato design and the strato barrel valve in the carb had a bit of oil mix in it so I sprayed everything inside and out with carb cleaner without disassembling it. 


I did a search and found out it has reed valves so maybe something is wrong with them but other than the basics I have no clue where to start. The plug is a nice tan color with a little carbon buildup. no obvious fuel leaks, fuel filter is new from last year. 

Where do I look next?


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## CTYank (Sep 15, 2014)

JONSSTIHL said:


> My leaf blower has started giving me trouble lately. It slows down at full throttle
> 
> Where do I look next?



You tell us nothing about its history, which is important.

Did you try adjusting carb, if that's possible?

Sounds like fuel system. First, change the in-tank filter, and flush out the tank. While there check the fuel line and if squishy or brittle, change it. Could also be tired carb diaphragm(s), which could call for a carb rebuild.


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## JONSSTIHL (Sep 15, 2014)

Sorry, the unit was bought in 2010 and I use it for residential purposes a few times during the summer for debris clean up and then quite intensively for a month in the fall for leaf clean up. I keep the fuel fresh. fuel filter is new and the fuel lines are good. First thing I looked at was to adjust the carb but you know how it is with these new units that they don't want us touching the carbs on. There appears to be two small adjustment screws recessed into small (less that 1/8 inch holes) in the carb body. 
they appear to be tiny d head screws but are not labeled H and L. 

I've done a little more research and it seems they just need to be tuned but these darn screws make it nearly impossible and the dealer can't sell you the tool.


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## JONSSTIHL (Sep 15, 2014)

the d shape on these screws is tiny, like probably only 1/16 inch in dia. A lot smaller than anything I have ever seen.


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## nmurph (Sep 15, 2014)

Fuel line collapsing, or it has a small hole that is causing it to loose vacuum.


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## LegDeLimber (Sep 15, 2014)

IF my memory serves correctly, the top of the screw is about 2mm or about .080 .
That nylock insert makes 'em a bit of a b**** to get out. 
I've got the dimensions somewhere , but between shifting hard drives in the pc and the brain fog 
after the knee work, I'm clueless as to where htings are now.

I stumbled across a factory slotted screw that's a repalcement for the little "D" heads.
I pretty well trashed the original ones in getting them out.
It took about 3 months for them to arrive after ordering though.

As far as the running issue, i'd guess the usual tank vent and screen in the carb.
I'd check that new fuel filter too, since it's easy to do.

also these pb-500 s were a bit lean, so i'd check the compression and look in the exhaust
just as a routine to be sure of conditoins of things. plus it's a good time for muffler mod then
while it's removed.

The reed system in them is interesting: there's a pair of petals in the intake block
and then there's one in the port caps at the end of those tubes that wrap around the cylinder.

hopefully I didn't loose the info I had, but I 'll keep looking for the rest of my pics and info.
may take me a littel time..still kinda got a skippy spot in the memory from things.


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## JONSSTIHL (Sep 16, 2014)

Had a little more time today to look into it so I took apart the carb and checked the diaphragm and they looked good, not torn and still flexible. put it all back together and tried it out and it didn't run at wot at all not even cold anymore so I figured I've got nothing to lose. I had kept the original fuel filter when I changed the fuel filter last year so I put the original one back in and low and behold it works. 

so plus one for the fuel filter atleast for now. I cut it open and it didn't look all that dirty.


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## JONSSTIHL (Nov 11, 2014)

just a quick update

the fuel filter only worked temporarily the intermittent bog is becoming less and less intermittent. 
threw a carb kit in it and cleaned out the carb and a new spark plug and the problem is still there. 

I'm really wondering about those reed valves on the side of the cylinder. I wonder what the symptoms of stuck reed valves are. 

the new plug did not fix anything and applying the choke doesn't really change anything. 

next step is a new fuel line and then it is off to the dealer to file a warranty claim before may 2015,
this pisses me off because the machine has 20 hours on it tops


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## TIMBERTRON (Nov 11, 2014)

did you presure check the carb or have you done a presure and vacuum check on the cylinder and seals and if your just starting to get a leak. and i would check the reed valves they can get stuck from time to time or just break.
what about the muffler port that could be carboned up and cause the unit not to go into full rpms


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## rmh3481 (Nov 11, 2014)

Clean out or replace the white 'jelly bean' tank vent. The engine is starving at wot. Pump diaphragm cannot over come the vacuum in the tank. 

I usually pull the guts out of the vent and put them back into service.


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## JONSSTIHL (Nov 12, 2014)

forgot to mention in my update that the tank vent is in the cap and is a rubber duckbill setup that is clean. I tried it with the fuel cap off and it still does it. the muffler is clean. It's the first thing I checked. the funny thing is that the choke doesn't seem to affect it. If it was lean I would expect the choke to help it run a little better. 

I haven't had time to do a pressure check of the crankcase and the carb was not pressure tested. I just cleaned it out and put the kit in. other than a little bit of corrosion inside the carb there was nothing unusual.


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## mountainlake (Nov 12, 2014)

If there's not enough fuel in the carb for what ever reason the choke won't help. Steve


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## rmh3481 (Nov 12, 2014)

If the vent is clear and its still bogging, your going to have to adjust the carb. 

Here is a link to the drawings;
http://www.echo-usa.com/documentation.aspx?s=pb-500h&c=en-us

Open the parts diagram, Page 7, Item 15 are the jets.


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## JONSSTIHL (Nov 12, 2014)

when I put the choke on it starts puffing black smoke at idle so it is getting enough fuel at least at idle. I'm reluctant to adjust the carb because when it is running right it is bang on 6800 rpm which is the max rpm spec in the owners manual. 

The adjustment screws are micro d head screws so I have to go to the dealer to have access to the tool.


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## stihl041avhog (Nov 12, 2014)

Yes the new epa sucks. You can cut a slot with a dermal tool if you want. It does sounds like the carb needs to be adjusted. Reed valves ? Got to check on that.


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## mountainlake (Nov 13, 2014)

Give the carb a good cleaning. Pay attention to the little inlet screen if it has one. Hows the fuel line? Steve


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## Saw Dr. (Nov 13, 2014)

We have seen several of those with leaking starter side crank seals. The last one, the seal actually came in half. The inner lip/garter spring sheared from the outer portion. I suspect they are not using enough (or any) lube on the seals at the factory. 

FYI, Echo will not have the deal in stock (in the unlikely event you can find an actual servicing dealer). Fastenall will show "no stock within 25000 miles of zip code xxxxx", though they can get it. NAPA can get it also, though several days lead time plus shipping. 

So what is the realistic fix? I assume you have leaves down, and would rather have it fixed sooner than later.... 

I have good news. The Stihl 1123 and 1130 series use a seal of the same diameter. You can find a MS 170 carcass at just about every Stihl dealer in existence. I have a couple of straight-gassed MS 250s that I have been scavenging for PB500 seals. Most dealers do not keep lose seals in stock, as the (few) customers who actually want them would prefer to get "fresh" ones when the need arises. 

Good luck. Obviously, this is all moot if the piston is scored. We have seen one scored due to that seal failing already this season.


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## LegDeLimber (Nov 13, 2014)

That intermittent bogging getting worse sounds like the way my pb-413 was acting last week.
This was the first usage of the 413 in over a year. Fired it up and after runnig about 2/3 tank of fuel
I began to hear an odd speed drop - bog every 2 or 3 maybe 4 mins. 
The blower's second hand , fuel lines are fine and the carb is a known good runner off of the 620 (yes it's a semi-redneck with a blower thing!) So I figured , "ehh probably the duckbill in the cap was another ethanol victim".
Well the faltering went from annoying to dang near wont run over about a 20 min stretch.
Hmm, need to address this little glitch I reckon.
Grabbed a "barely used" fuel filter and gave it a shot of carb cleaner, by back flow through the hose nipple then a very careful light blowout with the air hose.
Looked good enough for now, no ugly color or sticky ,gunky stuff
Fished out the fuel line in the blower tank and swapped in the cleaned filter.
Cranked 'er up and hasn't missed a beat since.

It was so dramatic that when it was done I really wished i had videoed it for a nice little posting about it.

as for the dealers not stocking a crank seal. Sounds sort of sad
considering that seal appears to fit a squatload of different machines.
http://www.ereplacementparts.com/oil-seal-p-520014.html?osCsid=sp495apkammhm39hkpn9fp7ul0


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## rmh3481 (Nov 13, 2014)

Great idea on scrounging seals Doc.

Crank Seal Part No Echo 10021300310, two of the same - one on each side. Called just now to see if the seals were available or special order, they are in stock for $5.

Carb was not in stock, $90 at Parts Tree, Echo A021001642. $150 via Walbro - http://wem.walbro.com/walbro/partnumbersearch.asp?ItemNumber=wla&submit1=Go!&ManuItemNumber=

Sounds like you will have to bite the bullet and adjust the carb. Maybe throw the blower in the back of your truck and take it up to the local Echo guy. Hopefully they will fix you up for a $20 tip? Have the plastic cover off so they can get at it when you get there. Im sure they will set it with a tach if its that touchy.


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## rmh3481 (Nov 13, 2014)

Echo part number for the adjustment tool on a PB-500H is 91059. 

Looks like the Chinese can send new knockoff fully adjustable carbs into the USA by the boxcar w/o a peep out of the EPA, but God forbid an American Citizen tries to buy a Walbro adjustment tool.


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## JONSSTIHL (Nov 13, 2014)

thanks for the p/n on the tool. I replaced the screen when I put the kit in but nothing looked really dirty when I had the carb apart. 

I will check out the seals this week end after getting the wifes winter tires on her car. 

the intermittent nature of the problem makes me think it is not an adjustment issue. just took a quick look at the ipl and there doesn't seem to be an impulse hose to tap into to pressure test the case.


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## Saw Dr. (Nov 13, 2014)

Just put your air chuck in the spark plug hole and blow some air in. It will be pretty obvious if that seal is leaking. Soapy water will make it even easier to see.


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## Giles (Nov 13, 2014)

JONSSTIHL said:


> My leaf blower has started giving me trouble lately. It slows down at full throttle
> 
> 
> It runs fine until it gets warm, maybe 5-10 minutes then it starts slowing down at full throttle every once in a while until it gets progressively worst and eventually I can't get it to run at full throttle. I can keep it running by letting off the throttle for a few seconds then returning to wot. the problem is intermitent so I can get the job done it just takes longer.
> ...



I have a Husqvarna backpack blower that was doing the same thing. I cleaned the carb--same problem. This model has NO adjustment screws!!
I removed the original fuel filter and cleaned and blow it out. Removed the muffler screen and discovered it has a catalyst muffler. I could see that it would be major to do a muffler mod, so I decided to just leave the screen out.
Bingo---used it all day yesterday with no problems.
If the problem returns, I will gut the muffler.


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## z71mike (Nov 14, 2014)

Giles said:


> I have a Husqvarna backpack blower that was doing the same thing. I cleaned the carb--same problem. This model has NO adjustment screws!!
> I removed the original fuel filter and cleaned and blow it out. Removed the muffler screen and discovered it has a catalyst muffler. I could see that it would be major to do a muffler mod, so I decided to just leave the screen out.
> Bingo---used it all day yesterday with no problems.
> If the problem returns, I will gut the muffler.


Can't gut the muffler if you can't adjust the carb to compensate.


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## Giles (Nov 14, 2014)

You are correct. But I can change the crappy carburetor to compensate.


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## rmh3481 (Nov 14, 2014)

The barrel carbs are adjustable. Their fuel needle travels down through the barrel. Recessed at the very top is a small plug that covers the needle. Raising the needle adds fuel. 

Here are the walbro service manuals;
http://wem.walbro.com/distributors/servicemanuals/

Select wyk and notice in the diagrams the needle running down through the barrel. The top acts as a ramp and raises the needle as the venturi opens.


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## z71mike (Nov 15, 2014)

rmh3481 said:


> The barrel carbs are adjustable. Their fuel needle travels down through the barrel. Recessed at the very top is a small plug that covers the needle. Raising the needle adds fuel.
> 
> Here are the walbro service manuals;
> http://wem.walbro.com/distributors/servicemanuals/
> ...


Yes, but you're still stuck with a static main jet.


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## LegDeLimber (Nov 15, 2014)

Hang on Guys, it's a walbro, WLA-1 on mine. For some reason I can't see a diagram of any of these series carbs, on the walbro pages.
But the FeeBay link has some shiny new pics of one.
http://www.ebay.com/itm/Echo-OEM-Carburetor-PB-500-Walbro-WLA-1-New-/140443261671

That black , barrel type section at the top is the air valve.
it feeds the two reeds through those hoses that hug the jug
and have a reed in each port cap on the cylinder sides.
Quad transfers, but one port on each side of the jug is favored to feed from the reed.

You can see the carb is still a throttle plate or shutter, type.
It alss feeds into the case via a dual petal reed.
I'm beat right now guys but gimme some time and I'll try find the photos i took 
as I tore mine down, thinking of maybe brave enough for a thread on it.

And I 'm still grubbing about for the needles and the number.
I had Realy nice neighbor come over to help around the house, brought me groceries and "straightened up" a bit WITH my permission and blessing ( after the knee port&polish job)
But.... between that and the "mini blackouts" I had with the first pain meds
I'm here to tell you guys it's like having Alzheimers at an Easter egg hunt.


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## LegDeLimber (Nov 15, 2014)

Here is the link to those elusive WLA-1 needles.
echo/shindaiwa # P003001130, H Needle same needle fits both holes guys.
http://www.ereplacementparts.com/h-needle-p-505315.html
When I went to dealer and orderd it took over 2 months for them to get here.
Order an get the needles in your hands first, then you can twirly tool those mini "D"s out.


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## z71mike (Nov 15, 2014)

I wish my WYA-155 was that easy!


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## LegDeLimber (Nov 16, 2014)

Is that WYA on a Redmax blower? I've got a few lean seized carcasses here that I grabbed a couple years back.
For what it's worth, the needle on these older carbs is adjustable. Just the main jets were apparently a couple sizes too small.


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## Saw Dr. (Nov 16, 2014)

All of the adjusting in the world will not solve this guy's issue of the seal is out. We tried on the first wonky one until we figured it out.


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## z71mike (Nov 16, 2014)

LegDeLimber said:


> Is that WYA on a Redmax blower? I've got a few lean seized carcasses here that I grabbed a couple years back.
> For what it's worth, the needle on these older carbs is adjustable. Just the main jets were apparently a couple sizes too small.



Yes sir. The main jet is the problem. I don't know why they did that. Terrible design. That's why I'm trying to find an adjustable replacement.


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## JONSSTIHL (Nov 17, 2014)

replaced the fuel line this weekend and it worked well for 10 minutes then the dreaded drop in rpm showed up. I managed to finish the job with it and so I'm done with it for this year. I will take it back to the dealer before the warranty is up this spring. hopefully they can find the trouble. 
I also took off the starter assembly and it looked awfully clean in there, I don't think the seal is leaking. 

maybe it is the ignition module because sometimes the rpm drops fast as if someone hit the kill switch but if I let off the throttle it idles fine. the ony way to get it to die is to hold the throttle down while it bogs.


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## LegDeLimber (Nov 17, 2014)

JONSSTIHL Just for giggles, swap in a fresh fuel filter or backwash the current one 
through the hose nipple, using something like carb or brake cleaner
and then Very Gently with a light touch blow it out with air. 
You don't want to blow it apart with a heavy blast, 
just a very light puff to push out the cleaner solvent and see that everything looks clean
and no nasty gummy deposits still in it.
That's all it took to stop that persistant bogging in my 413 that was much like what you've described.
The 413 is a unit I picked up as a parts donor for the 620 ( lots of common parts)
But after I got it home gave it a more thorough inspection , I realized it was in darned good
condition other than carbon clogged exhaust port. 
point here is that it was doing that run for 10~12 mins and falter a bit, but getting worse.
Shorter time till next bogg and almost die each time until you let it idle a moment.
Loosening the fuel cap didnt help, So I grabbed a spare fuel filter and did the cleaning routine
and swapped it in and Bingo! end of problem. 
Hey, come on it's cheap and easy to try!

z71mike I saw where you've asked the lawnsite crowd for ideas. I checked the jet in that carb in my photo and it seems to be the #61 jet. I also remember seeing some shortblock kits for the 8500 redmax last year on feebay
and the kits included a larger main jet.
I didn't see any listed with the jet kit, when I looked a couple nights ago.
so I guess it's time to grab a micro drill index kit and the #63 jet and just have a little fun.

For what this is worth, I swapped a metering body from the redmax blower carb 
onto the Echo PB-500 carb. This setup would let me adjust the pb-500 to a rich/light four stroking condition.
I was planning to raise the metering lever a small bit and see if that would get the extra fuel
to fatten up the top end, but had the other metering body laying loose so I just tried it first.
I'd expect we'd be better off to just drill out the main jet on the pb-500 rather than lifting the metering lever though as it could throw the mixture too rich in other speed ranges


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## z71mike (Nov 18, 2014)

LegDeLimber said:


> z71mike I saw where you've asked the lawnsite crowd for ideas. I checked the jet in that carb in my photo and it seems to be the #61 jet. I also remember seeing some shortblock kits for the 8500 redmax last year on feebay
> and the kits included a larger main jet.
> I didn't see any listed with the jet kit, when I looked a couple nights ago.
> so I guess it's time to grab a micro drill index kit and the #63 jet and just have a little fun.



I'm on the lookout for another carb so I can drill it. Really don't wanna drill out my one-week-old unit under warranty, in case I need to slap it back on for some reason. Waiting for the right deal to come around.


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## JONSSTIHL (Nov 18, 2014)

The machine is on it's third fuel filter. including the brand new one that is on it now. 
I even tried a different batch of fuel mix thinking maybe it was bad but still the same symptoms. 

one problem I may have is that when I cleaned out the carb I couldn't take out the mixture screws so maybe there is still a speck of something in the carb.


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## LegDeLimber (Nov 26, 2014)

z71mike said:


> I'm on the lookout for another carb so I can drill it. Really don't wanna drill out my one-week-old unit under warranty, in case I need to slap it back on for some reason. Waiting for the right deal to come around.



I can take a look in my carcass pile and see if there's nice looking one.
Sorry for not reading this and posting sooner, i've been stuck somewhere that I couldn't get online.


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## ackack (Feb 16, 2015)

New member & reviving this thread after a few months. Picked up a PB-500 off Craig for next to nothing. Piston & cylinder scored so I replaced but am still easily "in the money" vs a new blower. However, am having the same carb problem some have experienced ... only runs on 1/2 choke (but erratic) & stalls immed. when choke is moved to "run." Since the jug is new, there is no carbon at the exhaust port & the muffler looks good; arrestor is clear. Rebuilt the carb w/kit (also sprayed w/ cleaner & air blew it, plus ran it through ultrasonic cleaner), new fuel filter & lines. Did pressure/leak test w/air into cylinder & no leaks, crank seals solid. Thus, I suspect that the carb needs adjusting ... only thing left? LegDeLimber has great solution of swapping the "d" needles for Shindaiwa notched needles and they do look the same except for the head. He says "you can twirly tool those mini "D"s out." I tried an 22-18 electrical butt connector and it did slide over the "d" head but was not tight enough to twist the needle ... it just spun around it. Any other suggestions for extracting the "d" heads?


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## backhoelover (Jun 7, 2015)

tech school tough us that the reed valve has to be adjusted just right 
ill send you the spec as soon as i can find them


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## backhoelover (Jun 7, 2015)

ok
air vanes on side should be 0.43mm to 0.88 above mounting service 
here is pic for reed valves


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## JONSSTIHL (Jun 8, 2015)

I ended up breaking down and taking it to the dealer. It was sucking air when we pushed the primer bulb so we swapped another new fuel filter on it and it seems to be running better. by the time I brought it into the dealer I had fiddled with it so much that I didn't know if the fuel filter that was on it was the new one I had just replaced or if I had gone back to the original one while trouble shooting. 

I need to go back because it is a little too rich. it is turning 6100 rpm at wot and it should be 6800 rpm. 

At this point I would pay 50 bucks for a micro d head screw driver but I can't seem to find one.


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## JONSSTIHL (Jun 8, 2015)

thanks for the info on the reed valves. I was wondering what those little black boxes looked like on the Inside. Any adjustment possible or is it replace with new if not within spec.


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## backhoelover (Jun 8, 2015)

I'll send u the link to show u where u can buy single d carb tool when I get home from pc


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## backhoelover (Jun 8, 2015)

you get my info from carb tools


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## JONSSTIHL (Jun 8, 2015)

yes thank you very much, they are more expensive than I thought but it sure beats another trip to the dealer


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## backhoelover (Jun 9, 2015)

I forgot to send u the service data for that unit i will when I get off work


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## backhoelover (Jun 9, 2015)

here you go i can get small single d carb tools who wants to buy one


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## backhoelover (Jun 9, 2015)

check out my pic that is my carb adjusting tool collevtion


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## backhoelover (Jun 9, 2015)




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## JONSSTIHL (Jun 10, 2015)

thanks for the info, I stopped by my local dealer and he could get me the 91059l for 25$ so I jumped on it. I didn't need the large D screwdriver so the 91100 was more expensive. 

I couldn't find the 91059L anywhere online


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## JONSSTIHL (Jul 9, 2015)

got my screwdriver last week and finally got around to tuning it. anyone have any idea which screw is the H and which one is the L


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## z71mike (Jul 12, 2015)

Use the process of elimination.


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## JONSSTIHL (Oct 22, 2019)

she is doing it again. and I can't remember what fixed it the first time but I will check the adjustment again. anyone have any idea which screw is the H and which one is the L.

this is really troubling because the problem is so intermittent it isn't funny.


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## LegDeLimber (Oct 23, 2019)

If memory serves me, the High is closest to the engine. Low is on the left towards air filter.
My pb-500 is out on loan to a friend, otherwise I'd could just go take a quick look.

After I changed the metering block of the carb, it quit fighting me and I sort of drifted off to other things.
https://www.arboristsite.com/commun...s-at-full-throttle.263144/page-2#post-5039226

Prior to that I had made sure the reeds (all three locations) were pretty flat and had no bad gaps at rest.
The intake reed had one petal that sat a bit open, so I flipped it over.
hmm, doing This actually put the burr side -away- from the reed block too.
As you would expect, that made cranking the blower noticeably easier.

Do NOT forget to use a thread adhesive IF you so much as touch the reed screws!
Clean and de-oil the screws (and the holes) before applying the it, or it won't hold.
Failure to do this properly, will very likely result in a destroyed engine when a screw comes loose.


A touch heaver than 50 to 1 for the fuel oil mix helps keep the reeds "wet" and sealing better.
I've used 3.5 ounces to a gallon (Echo Red Armor oil) and for the last few years am pretty content with how things .....start, tune and run.


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## JONSSTIHL (Oct 24, 2019)

thanks for the reply, I usually mix my fuel 45 to 1 just to be safe and I haven't fiddled with the reeds yet. I saw a youtube video where the guy said the H was closer to the air filter so i went with that and seems like that worked. my L jet was a little off and come to think of it. since the last dealer adjustment It would take maybe a minute to clear out after starting with the choke on. I would seem to run a couple hundred rpm lower for about a minute then go back up to regular rpms. 

I moved the H jet around a bit to clear out any possible blockage but the L jet seems to make the most difference. used it for maybe an hour today and it didn't bog. hope it is fixed.


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## backhoelover (Oct 25, 2019)

Which carb is in the pb500


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## backhoelover (Oct 25, 2019)

Need go pull carb and check little screen inside. There bad about swelling shut on walbro’s. No so much on zama


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## LegDeLimber (Oct 26, 2019)

Bugs me that I'm probably backwards on the needle positions. 
(forgetting a little too much nowdays) Would of sworn that I had photos of my efforts, but now I can't find them.

Carburetor is the WLA-1. Don't know why I can't find an image with the needles marked for h & L. Seems like most listings even skip them in the parts numbers list.

I see there's an aftermarket carb now.
https://www.amazon.com/KIPA-PB500-PB500T-PB500H-EB508RT-x/dp/B078V3F8S1

Last time I checked (a few years ago), Walbro wanted about 8~9 times that much for the OEM unit.
Walbro made 4~5 venturi sizes in that body style. All of them were danged expensive then.
Yes, the blower has the smallest one. I thought about opening the venturi size of mine, But was too expensive if I goofed it up. 
A new carb cost almost as much as a running blower was worth (at that time).


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## LegDeLimber (Oct 31, 2019)

Just saw my inbox. Thanks backhoelover !
Yeah I had the order of the needles backwards. Low is closest to engine.

Freaking body aches are killing my rest and ability to concentrate.
Seems like this was stuff I messed with ever week and would not forget.
Then health issues push things aside and before you realize it, the details are slipping away.


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## ri chevy (Dec 2, 2019)

OK Just to Clarify here...
The H screw is on air filter side (Left when looking at the carb adjustment screws) and the L screw is on the engine side (Right when looking at carb adjustment screws)? 
Thanks.


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## SEAM (Dec 2, 2019)

"L" is usually near the throttle butterfly (engine side) and "H" near the choke butterfly (air filter side) on regular carburetors. On rotary carburetors this rule may not apply and on the WLA-1 there should be only 1 screw for idle adjustment, though.


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## JONSSTIHL (Jun 29, 2021)

well, Sorry to revive a old thread but this problem keeps coming up. Every time I have had this problem a carb adjustment has cured it until the next season. I just replaced the spark plug and will try and tune it. I noticed the idle is a little low but still within spec. 

Any ideas why the H screws seems to have no effect. atleast not with small adjustments I'm used to chain saws where 1/8 turn makes a big difference and this blower seems like 1/2 turn makes no change on the TACH.


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## SEAM (Jun 29, 2021)

At high speed blower engines run under full load, making the adjustment less perceivable. This also implies that the engine is easily adjusted too lean without noticing. A lot of blowers are killed that way...


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## mountainlake (Jun 30, 2021)

I adjust the high on my blowers holding the throttle wide open and then for max rpm. To lean or too rich they slow down. Steve


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## SEAM (Jun 30, 2021)

Leaning out during operation may also be a sign of a clogging fuel filter...


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