Husky 350 with what appears to be a serious air leak

[atlarge54]

I loaned out a husky 350 that I built a few years ago (flat top piston, mild transfer work, opened up muffler). I get the saw back and it won't idle except at very high speed. I know, vac/pressure test is what is needed. It does have the metal clamp on intake boot.

Here's my question: The Husky 350 has different style seals than most saws. With 3, 4, maybe 5 years of cutting firewood and absolutely zero maintenance the air filter was SERIOUSLY plugged. Would a plugged air filter lead to crank seal failure?

 

[Jasent]

If the seal was weak it’s possible. It’s gotta get air some where. Weakest link gives

 

[grizz55chev]

I loaned out a husky 350 that I built a few years ago (flat top piston, mild transfer work, opened up muffler). I get the saw back and it won't idle except at very high speed. I know, vac/pressure test is what is needed. It does have the metal clamp on intake boot.

Here's my question: The Husky 350 has different style seals than most saws. With 3, 4, maybe 5 years of cutting firewood and absolutely zero maintenance the air filter was SERIOUSLY plugged. Would a plugged air filter lead to crank seal failure?

Never seen the seals fail, but I've seen the bolts holding the clamshell work their way loose causing an air leak.

 

[Bob Hedgecutter]

You have cleaned the saw up to see if the problems still exist?

If a saw is not periodically "cleaned" with the like of a blow off gun on an air compressor- all kinds of things can go wrong. Would it bust the seals? Probably not directly, but through other circumstances- possibly.
Could be that much debris getting in past the filter that the case and bearings are full of gunk that cause bearing wear and therefore flogged out seals. Heat does bad things to saws- dirty saws carry more heat, if the air cleaner is clogged and 4-5 years of zero maintenance- you can bet the rest of the saw is not too pristine!

Your symptoms might just be shite in the carb, partially blocking low circuit galleries.
Sounds like it needs a full tear down and all wear items replaced.

You are correct though- pressure and vac will confirm or deny.

 

[atlarge54]

Thanks for the replies. I'll clean and inspect before getting in too deep. Wish I had a known good carb to swap onto the saw, never had the greatest luck cleaning saw carbs.

 

[Clyde85]

I had a 350 that the cylinder screws would work loose on it.

 

[Wood Doctor]

Have you checked the compression? Last time I loaned out a chainsaw it came back straight gassed. Compression was shot and I had to rebuild the top end ro save it.

 

[Woodslasher]

I loaned out a husky 350 that I built a few years ago (flat top piston, mild transfer work, opened up muffler). I get the saw back and it won't idle except at very high speed. I know, vac/pressure test is what is needed. It does have the metal clamp on intake boot.

Here's my question: The Husky 350 has different style seals than most saws. With 3, 4, maybe 5 years of cutting firewood and absolutely zero maintenance the air filter was SERIOUSLY plugged. Would a plugged air filter lead to crank seal failure?

I'm playing the find the air leak problem on one of those right now. Fire the saw up and spray carb cleaner at the various joints. On mine, the initial problem was at the case/clamshell joint but it later turned out the carb wasn't sealing against the intake boot as well.

 

[grizz55chev]

I'm playing the find the air leak problem on one of those right now. Fire the saw up and spray carb cleaner at the various joints. On mine, the initial problem was at the case/clamshell joint but it later turned out the carb wasn't sealing against the intake boot as well.

I strip it down, block the ex and intake, pump 8 #'s of air into it then dunk it in a tub of water, then look for bubbles. That's only after a vac test failure, guaranteed to find even the slowest of leaks.

 

[Woodslasher]

I strip it down, block the ex and intake, pump 8 #'s of air into it then dunk it in a tub of water, then look for bubbles. That's only after a vac test failure, guaranteed to find even the slowest of leaks.

I did that roughly a dozen times, it just took awhile for me to think, "Maybe my means of blocking off the intake boot isn't the problem and the carb to boot seal is actually where the leak is".

 

[Huskybill]

On mine the cylinder adapter block was warped. Some sanding on a flat Castiron surface plate fixed that. The bolts were too long.
Maybe someone with more knowledge will chime in?

 

[Bwildered]

On my 350 the carb cap bolts were loose & wouldnt seal , when I tried to tighten them they just stripped out of the boot flange, then I put some zip ties through the stripped holes, the one of the zip ties wasn't located properly and got under the gasket , so It had an air leak and picked up exhaust side of the piston, got a new piston & rings for $17 , cleaned up the bore transfer, got longer cap bolts and put nuts on the other side of the boot flange to hold the carby on & bobs your uncle.

 

[Wood Doctor]

"bobs your uncle" --> There you have it. I must admit I have never heard of that expresssion. I supposed it's straight from Australia or New Zealand. Here's what you may have done to the boot flange:

This worked for me.

 

[Bob Hedgecutter]

"bobs your uncle" --> There you have it. I must admit I have never heard of that expresssion. I supposed it's straight from Australia or New Zealand.

No, not Australasian- though we do use it, the origins are very British.

 

[Huskybill]

Very British like stiff upper lip? I met some aussies in our engineering group with that brogue I listened carefully. My hearing was going anyway.

 

[KASH]

You hear the odd older fellow here in Canada use the expression.
As sure as Bobs your Uncle
Kash

 

[Bwildered]

You hear the odd older fellow here in Canada use the expression.
As sure as Bobs your Uncle
Kash

The rest goes "and Fanny's your aunt "

 

[Doug H]

I just finished repairing a Husky 350 that would run with a prime in the carb, but would not run after the prime ran out. I suspected lack of fuel, so I went to the usual suspects; fuel from the tank, adjusted the carb (after removing limiters), then removed, cleaned and inspected carb, then changed diaphragm, then changed carbs (had a spare from a 357xp. No luck. Went to crankcase vacuum problems- Removed and tested impulse line and intake boot, they were OK. Couldn't check crank seals with no vacuum tester, so I decided to check the cylinder base gasket. All 4 screws were really under torqued ( previous owner's work). So I removed cylinder to check the base gasket, piston, ring and cylinder and impulse hole. It all looked good, so I reassembled with Triple Bond on gasket and properly torqued cylinder screws. Same problem. During a final inspection, I discovered one of the 4 bottom clamshell bolts was missing! I had to remove the tank/rear handle assembly to get to the bolts. And of course, the 3 remaining ones were very loose ( PO work again). Replaced missing bolt and torqued them in. Saw works great now, no issues. Guess the crank seals must be OK. Cleaned as I went, so at least the saw is spanking clean inside and out now. Wish I had seen Grizz55chev's post about the clamshell bolts first, would have saved me a lot of unnecessary work. Need to always check ArborSite first!

 

[a. palmer jr.]

I will say that on the Husqvarna clamshell saws don't be afraid to use a little Dirko on the seals between the block halves even though it doesn't come that way. Every one I've put together without sealing it up leaked and cost me a lot of time so I make it part of the regular procedure now..

 

[Chevboy0167]

Blue or medium strength Loctite thread locker is your friend here also. I even use it on ALL bolts, nuts and even plastic screws!