I rebuild stihl chainsaws all the time, so I am not new to this. Latest one is a ms250. Big this was, crank was worn where bearings sit. Called stihl and the said that the 025, which I have a parts saw, is the exact same crank. So I swapped over piston. New parts, bearings, seals, all new lines, carb, air filter, plugs and a few minor things as well. All back together and it will not fire, not even on starter fluid. Now I double checked things. Crank is identical to one removed. Coil is adjusted properly and I have great spark, great compression, fuel is through carb and into motor, new gas, no carbon build up on exhaust side or in exhaust, flywheel key is NOT stripped off. I have checked that where piston is on stroke n when spark will fire, that coil and flywheel is all lined up. Now I am a bit baffled.. figured I would check to see if I have any other coils for this saw and try them, even though the one I have is working and I have good spark. Does anyone have any ideas or thoughts?
Stihl Ms250 Won’t Run
- Thread starter Bear1088
- Start date
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medalist
ArboristSite Operative
I'm thinking it would need to be way out of time for it not to fire. Maybe compare the old flywheel to the ms250 and check magnet/key alignments.
Just guessing of course.
I've heard many users complain at the ability to easily flood on start but assumed you are principal user/owner and you are way past this issue.
Good luck.
Just guessing of course.
I've heard many users complain at the ability to easily flood on start but assumed you are principal user/owner and you are way past this issue.
Good luck.
i have suffered a terrible no start i found to be a failed new spark plug and the used plug was bad too, both would give a blue arc when tested out of the saw....had a coil spark through its case once too that had good spark when tested..figured that one out at night LOL
Tigwelder83
ArboristSite Operative
I had one that was super temperamental. If you didn't catch it just right it would flood. Had it at 3 different saw shops, finally an Amish shop fixed it right... I traded it for a jonsred 2165, and smiled.
Wish I could find a shop that could address mine. Any idea what the Amish shop did? Where was the shop located? I suspect a long ways from me southeast of Pittsburgh.
Tigwelder83
ArboristSite Operative
I dunno what he did, I left with a different saw...
medalist
ArboristSite Operative
Not being intimately familiar with the MS250 I see in parts they use the choke flap built into the carb.
I'd either put a small bend in the linkage to reduce some throw or drill a hole in the choke flap to give it some air.
Good luck.
