This saw is about 15 years old and just out of stihl dealer for new carb kit and adjusting . After stalling when i try starting it the starter rope is very jerky and hard to pull . It eventually starts but stalls often . What could be causing this ?
Stihl stalls often . ms250
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Jetfixer1
Member
Here are a few things I do first off when a customer brings me a stihl saw that is running weird. 1 is the fuel lines crack after a few years where they go into the tank causing weird running issues. 2 is I take the fuel filter off of the line that is in the tank and blow out with compressed air.3 I remove carb and completely disassemble and clean I can't tell you how many times I get a saw that has just been "serviced" and I find the carb with dirt and moisture present.4 I clean the spark plug or replace and then I warm the saw up and re tune carb.
Jon1270
Minister of Fire
Was it behaving this way immediately after the dealer service? If so, I'd probably take it back and let them figure out what they did wrong. Failing that, I'd start by trying to find the source of the jerkiness and resistance when starting. Do you hear any odd noises when pulling the rope? If you remove the spark plug and recoil housing and rotate the flywheel through several full revolutions by hand, does the motor turn over smoothly? With the plug removed, the only meaningful uneven resistance you should feel while turning the motor around is the pull of the flywheel magnets as they pass the ignition coil, and the only noise you should hear from it is the normal fwop-fwop-fwop of the piston slipping through the bore and pushing air around. While you're at it, note the color of the tip of the spark plug. Try that and tell us what you observe.
One other thought -- have you noticed liquid gas spilling/being blown out of the muffler? Just this week I bought a much older saw that behaves this way. I haven't fully diagnosed it yet, but my best guess is carb problems are allowing so much gas into the motor that it basically hydrolocks. I suspect a bad metering valve.
One other thought -- have you noticed liquid gas spilling/being blown out of the muffler? Just this week I bought a much older saw that behaves this way. I haven't fully diagnosed it yet, but my best guess is carb problems are allowing so much gas into the motor that it basically hydrolocks. I suspect a bad metering valve.
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LocustPocust
Burning Hunk
Ethanol gas causes stalling issues in my Poulan saw. It would run for 20 minutes then quit and It wouldn't run again until the next day. Since I switched to Non Ethanol it will run all day, tank after tank.
I removed the spark plug and pulled on the starter rope and it pulls normal . Also examined fuel lines etc and a+ ok . While i was at it i put in a new spark plug and the pull rope is still jerky but not as much . I started the saw home and let it idle for 10 minutes without stalling . i will only know for sure next time i go in the woods . I always bring a spare saw a Husky ( as old ) and that one rarely fail . But i don't like the feel of it and would rather use my stihl . Thanks for the comments and i will keep you posted .
DodgyNomad
Minister of Fire
Have you adjusted your idles? LA and H might need to be tuned. Do a quick google search on MS250 idle adjustment, lots of data out there. I've had mine need adjusting over the years when it was stalling after I'd set it down or swing it around quickly at idle.
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