371 Air Leak

[decableguy2000]

I have an Ebay special 371 that I bought, that was advertised has having an air leak. I went through it with a fine tooth comb, new seals, gaskets, P&V tested less than a 1/4 tank later air leak. It was on the clutch original, I don't have tore down yet, but have a feeling its there again. Anyone have a better way to see where its coming from on that side of the saw. Its real busy in there. Also do you install the seal and then the sleeve or the sleeve than the seal

 

[Coutu]

http://www.arboristsite.com/community/threads/372xp-clutch-side-seal.161859/

Apparently that little o'ring can cause running issues. How bad does the saw race?

 

[jmssaws]

New seal and a new sleeve and a new oring and some sealor and then you throw it straight in the trash.

I've been battling these bleeping saws for a month trying to stop the airleak there.

I start putting the seal on the sleeve then installing it all together.

It's the sleeve that leaks and some anaerobic sealor is supposed to fix it but I don't have any.

044 is the same setup and I've never had one leak.

 

[Mattyo]

I could have sent you some anaerobic jason... wish I knew u were out

 

[Mattyo]

 

[jmssaws]

I could have sent you some anaerobic jason... wish I knew u were out

I got some comin

 

[decableguy2000]

Replaced the o-ring when I had it stripped to the bare case. Are you guys using the anaerobic sealer under the sleeve on the crank? I use it on the the bolts for the oil pump. I wonder if the sleeve has a small burr on it some where tearing up the seal. As far as the racing, it ran up to 14.2/14.5k rpm, it didn't want idle well after the cut as well. I know I buggered the sealing surface on the flywheel side getting the old seals out. I put a thin layer of motoseal on the out side of the new seal, and P&V tested fine. I'm half temped to sell all my older saws and buy 1 new one.

 

[Coutu]

Replaced the o-ring when I had it stripped to the bare case. Are you guys using the anaerobic sealer under the sleeve on the crank? I use it on the the bolts for the oil pump. I wonder if the sleeve has a small burr on it some where tearing up the seal. As far as the racing, it ran up to 14.2/14.5k rpm, it didn't want idle well after the cut as well. I know I buggered the sealing surface on the flywheel side getting the old seals out. I put a thin layer of motoseal on the out side of the new seal, and P&V tested fine. I'm half temped to sell all my older saws and buy 1 new one.

No need to sell all your older saws; this place has a wealth of information, and most importantly, people that will take time out of their day and go out of their way to help you. Truly a great community here.

I was told when roofing to think like water.

Maybe thinking like air when working on saws would be a good thing?

 

[Chainsaw Jim]

Is a brand new sleeve sloppy on a brand new crank?

 

[Mattyo]

If there is a line scored in the flywheel side case itself ...where the metal seal goes, i'd toss the case half unless you can weld it up. The likelyhood of getting that to seal is pretty low. it sucks to toss cases, but there are plenty on ebay and you can always buy the am cases for pretty inexpensive.

on the clutch side, some anaerobic on the crank and the inside of the bushing would be where I would put it. if its having trouble returning to idle, i would think the leak would be fairly obvious, or some other issue in the carb.

and though I only use trashed saws that I have rebuilt, i understand the sentiment to use new saws. if you have a business, and need things to function, sometimes it is best to sell the old and go with new with warantee... just the cost of doing business. sometimes you can mix hobby and business, but most of the tree guys I know don't want to be bothered with fixin saws.

 

[Duce]

Bushing should be smooth, new o-ring, motoseal, sealant on oil pump bolts and clean all surfaces well. Have had seal leak between case and seal flange, use Motoseal and vacuum to draw sealant in, let is set up and done. For those that cannot stop leaks, please don't trash and I will cover shipping.

 

[decableguy2000]

Went back out to the tool shed, finished breaking down the saw, finished a beer, now I'm at a loss. sealed up the case with OEM plates pinched the impulse off. Took it to a bucket of water and pumped it up to 10psi held for 30 min while turning the crank no bubbles not even from the decomp or around the plug. Than I switched to vacuum, pulled it down to 10in Hg, again held for 20 minutes while turning the crank. At this point I'm scratching my head,
Thinking fuel system now. Pulled the fuel line out of the tank and again P&V tested and no leakage. I have one more HD12 that I haven't tested or pulled apart I just received in the mail. I also have an aftermarket carb to play with. I need to order a couple of small things so I'll add a fuel line and filter. The tank vent appears to be clean and functioning.
Any ideas?

 

[Mattyo]

if it aint a leak, i'd start with swapping the carb.

 

[5000+]

If there is a line scored in the flywheel side case itself ...where the metal seal goes, i'd toss the case half unless you can weld it up. The likelyhood of getting that to seal is pretty low. it sucks to toss cases, but there are plenty on ebay and you can always buy the am cases for pretty inexpensive.

on the clutch side, some anaerobic on the crank and the inside of the bushing would be where I would put it. if its having trouble returning to idle, i would think the leak would be fairly obvious, or some other issue in the carb.

and though I only use trashed saws that I have rebuilt, i understand the sentiment to use new saws. if you have a business, and need things to function, sometimes it is best to sell the old and go with new with warantee... just the cost of doing business. sometimes you can mix hobby and business, but most of the tree guys I know don't want to be bothered with fixin saws.

Why would you scrap a case for a scratch the seal pocket? Many simple ways to solve, plus it is in a no wear area.

 

[Mattyo]

first off, its just a case side ... 2ndly if you are relying on a piece of equipment and don't have time to fiddle with it, then best to get a case half that doesn't have a scratch, third, IF you get a recurrent leak in that spot you will eat up an expensive top end plus waste time doing the rebuild...again.

if you are a hobbiest and want to slap some JB weld in there then go for it. probably not a good idea if you are a professional though. my 2 cents

 

[decableguy2000]

Left it hooked up over night and didn't drop vacuum 12+ hours. Spun it with a cordless drill still holding vacuum. I'll spin it with a corded drill when i get home from work, if I can find one in bowels of my shed.

 

[Mattyo]

so....it doesn't have an air leak at the seals... the problem is elsewhere...

 

[decableguy2000]

so....it doesn't have an air leak at the seals... the problem is elsewhere...

Maybe, I going to screw around pressure and vacuum testing it a little more, I'm going to pick up a new fuel line and filter for giggles this week, I have an extra HD12 that I don't every remember trying on anything as it still has the limit caps on it. I pumped it up when I came home for lunch, and after dinner I'll check it and see. I have never had a carb cause a saw to race before. However when I pulled the fuel line off I didn't get a splash of gas as normal....


By the way I enjoy your videos

 

[Mattyo]

If the crankcase holds pressure and vac for even a few minutes it's ok...look elsewhere. ...and keep it simple

 

[jmssaws]

Fuel line