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I have a Husqvarna 357XPG chainsaw that I bought in in early 2000. It has been a great chainsaw and I do not want to part with it. It operates at 14500 rpm and has heated handles. Great for cold winter work in Wisconsin.
Earlier this summer I operated it without properly mixing the fuel before adding it to the tank and scoured the piston and cylinder. A repair facility told me it wasn't worth repairing. So I bought a new piston and cylinder kit and installed it my self.
The carburetor is a Walbro HDA 174. I have dissembled the pump diaphragm side, the inlet needle valve side of the carburetor and cleaned everything. The metering lever appears to be even with the diaphragm plate. The manual says the idle needle and high speed needle should start out at 1 turn from closed.
The saw starts on the first pull and runs for a short time, maybe 4-5 secs, before stopping. With the air filter removed fuel is misted from the intake of the carburetor. It is obviously getting too much fuel. Can anyone give me an idea of what I should do next?
I have not done a pressure test of the metering inlet valve nor checked the cylinder compression yet but plan to do so.
 

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1. Carburetor screw settings given in any manual are initial settings. Fine tuning is usually required with a tachometer and/or an experienced ear.
2. Fuel misting out of a piston-ported 2-stroke is normal. Most have a spit-back cup or foam element to catch it. The air filters on some products have it built-in.
3. The quality of the cylinder kit may be a factor, if it wasn't OEM.

As for what to do next, that's difficult. There could be: a crankcase leak; an impeded impulse port or kinked hose; a restricted carburetor; a plugged fuel filter (if primer equipped, a plugged f/f or restricted carb. inflow-system usually results in the primer returning slowly or staying depressed). If it's truly getting too much fuel, then the plug would be very wet when removed after stalling.

Whenever a 2-stroke scores, it's important to try and determine WHY it scored, else a repeat failure may occur. Often it's the carburetor at fault, being restricted which leans out the mixture. Or, it can be as simple as having stale fuel, low octane fuel (either when purchased or due to phase separation), water in the fuel, or overloading resulting in over-heating (such as when leaning on the saw due to a dull chain (rather common)). A crankcase leak can also precipitate a failure - this includes the intake system.

So, you may have addressed the symptom, but not the disease. At this point you may want to have a pro evaluate it, if they're willing to work on the saw. I would be reluctant to work on it without performing a crankcase pressure-vacuum test. Without a pro diagnosis, I can only speculate that it probably needs a carb. rebuild.
 
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