I have a MS362 that I've cut a lot of wood with. I love the saw. It idles great forever but as soon as I touch the throttle it stalls. I've reset it and I'm leaving towards the ignition. Thanks for any help.
MS362 idles great. Stalls immediately when throttling
- Thread starter Cmuwayno
- Start date
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ShneaSIG
ArboristSite Operative
Can you check the fuel line and intake filter? A split or hole in the line will cause this pattern, and it's one of the easier things to look into.
ShneaSIG
ArboristSite Operative
My pleasure - I'm a novice at this, but when I have had a balky 2-stroke that has seen some use, and this problem developed, it's always been a split or rupture in the fuel line. It seems the material just breaks down over time and needs to be replaced, sooner or later. Over the years I've had this condition with a couple weed-whackers, and I know my dad had it one or twice with a long-running saw. I've never experienced it, but I've heard a clog in the intake filter can do the same.
You have a lean condition right off idle, either an air leak, bad fuel line/filter or a plugged up high speed jet.
Van462
ArboristSite Member
Is the saw an Mtronic or standard carb?
Van462
ArboristSite Member
Could be the fuel solenoid. The default state is full open. Once running it supplies voltage to moderate the fuel control. Check your plug to see if it looks wet. If could be running so rich at idle that the crankcase is loading up with fuel and then once you open the throttle a bit it goes so rich can't support combustion. If you open the mtronic test port, then measure with a meter it will read around 33 ohms. There is a solenoid check you can do to see if is moving properly as well. I believe the solenoid has a 2 year warranty from other post I have read. If you get the saw warm you may be able to get it to run a bit at higher rpm but it will still be very rich.
Also remove your bar and chain to remove any issues with the clutch engaging and possible loading the motor to early.
Your dealer should do the leakage test for the solenoid valve. With that you know for sure if it is leaking or not.
SteveSr
Addicted to ArboristSite
If this was a standard carb saw... A main nozzle check valve that is stuck closed can also cause these symptoms. Usually this will manifest as intermittent... Runs fine one day but not the next.
Hello all and thanks for the info. Two things first; I am fearless with a wrench but I am a novice so take my posts any way you choose. Second I have teenagers so the delays are unavoidable....update....the saw will rev and run great once in a while upon cold startup. It is getting fuel so I decided to year it down. I replaced the jug and case due to a stripped out plug thread on the case. I helicoiled it and it continued to blow the plug out. After I ran it a few tanks I experienced the stalling problem. I finally tore it back down. Here are pictures. Maybe it was stalling because of blow bye due to the wear. There is some scoring on the side. Next step is??? I enjoy this so I'm not in a huge hurry. Of course I want my saw fixed. Thanks again, Wayno
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SteveSr
Addicted to ArboristSite
Wow! that looks like a severe case of pre-ignition and subsequent overheating leading to a roached top-end.
What is your location, what kind of fuel were you using, and how old was it.
I don't know if a leaking spark plug (or de-comp valve) could lean it out enough to cause this issue. It is interesting that the M-tronic control didn't have enough range to compensate for or shut-down the saw to prevent this catastrophic damage.
What is your location, what kind of fuel were you using, and how old was it.
I don't know if a leaking spark plug (or de-comp valve) could lean it out enough to cause this issue. It is interesting that the M-tronic control didn't have enough range to compensate for or shut-down the saw to prevent this catastrophic damage.
Van462
ArboristSite Member
Looks like Ironman nailed it on the second post with the lean call. Mtronic works great but as it has no sensors in the exhaust to monitor A/F ratio. Air comes in from the path of least resistance. Whatever doesn't flow thru the carb gets no premix. Likely needs a new piston and cylinder. Then pressure and vac check to verify its air tight. You could use the existing cylinder to do pressure and vac test to confirm the condition of the case. Its worth checking the crank for discoloration and the connecting rod for play.
Awesome news. I had the same thought in a much simpler form. I ordered a new piston and cylinder. I will check the crank and rod also. I will report back. Thanks a ton for the expertise, happy Independence day and Godspeed! Wayno out
