Husky 455 Fuel Tank Pressurizing

[Two-Smoke]

Recently inherited an 08 Husqvarna 455 from my father in law.  He had been fairly rough on it cutting allot of firewood and neglecting maintenance in several areas.  The saw had sat with gas in it for the last 3 years or so. When I got the saw it started up but after 5 minutes of running it the motor started to run erratically.  From there I decided to try and clean it up to get it back to "reliable condition".  First I took the air compressor to it and blew out the years of sawdust caked in every imaginable location, replaced spark plug, replaced fuel filter, replaced air filter, rebuilt carburetor (diaphragms, gaskets, cleaned screen, cleaned ports), replaced primer bulb, replaced fuel line from carb to bulb, replaced fuel line from bulb back to tank, replaced tank vent.  Started the saw, got carb tuned using inductive tacometer, and test ran saw.  It runs great until the motor gets good and hot causing the fuel tank to pressurize resulting in the saw stalling while idling.  I thought replacing the tank vent would cure this issue but it has not.  The only thing on my radar which I have not replaced is the fuel line going from the fuel filter up into the bottom of the carb.  I just took it off a few hours ago and inspected it finding no holes, tears, or leaks.  Any help would be much appreciated.  Thanks in advance.

[Spike60]

Saw may need a new carb, but before spending any more money make sure you're not fighting marginal compression.

Not every carb will take a rebuild, which can be frustrating. Sitting for several years with old gas, cleaning is difficult without an ultrasonic cleaner to disolve all deposits. And any oxidation/corrosion on the carb body itself cannot be corrected with a carb kit.

[fossil]

The tanks on chainsaws all build pressure as the fuel heats up or just from vibrations and shaking.

The tank vent lets air in but not out.

[Two-Smoke]

Spike60, I assume marginal compression refers to the compression the engine is making.  If so, the compression is good, it takes a good effort to pull the starter without the decompression button pushed in.  I checked the piston/cylinder for scoring as well and all is good there.  When I run the saw without the cover on and look at the two fuel lines going into the fuel tank I can see fuel slowly oozing out as i rev the engine.  I test ran the saw last week and put it away to go visit family.  When I came back i could see where fuel had been oozing out of the tank vent and up through the grommets at the two fuel lines that go into the tank.  All this was happening without the saw running.  Thanks again for your feedback.

[sablatnic]

The fuel lines have probably shrunk, so fuel is leaking around them. It will flood the engine at idle.

[Real1shepherd]

After replacing fuel lines, replace the grommets as well. Make sure they are gasoline rated; If in doubt, soak them in gas for a few days and examine.

The Swedes over-complicated their gas venting system in saws and now a lot of the OE parts are NLA. The Husky 2100/2101 is a classic example. Sometimes, just a tight fitting grommet and a small plastic gas vent is all you need.

Old J'reds for example had a vent tube that went across the airbox/carb and out through a little hole in the case where the flywheel is. An in addition, they used a little insert sinterered bronze piece to keep dirt out. Only an engineer could come up with that.

Kevin