Stihl ms 250 idle isue

[merc_man]

My son has a POS ms 250 that is really starting to piss me off. That was my rant lol

Ok so i presure tested it a bit ago and it did have a little leak where the lower end of the motor bilts of. Fixed that and no leaks.
It has alway been a finicky saw for idleing.
Put a carb kit in oem carb while back and still no better. Tried an aftermarket carb and still no better.

So i have always had this feeling that its something to do with the coil. It runs perfect WOT and come down to idle fine then couple seconds later it either will stumble and continue to run or just shut off. Even if it continues to run after it stumbles it will donit again. Anyone else have any ideas to tro.

Fuel lune does not leak. It is original
I do have a chinese one i could try if anyone thinks that may ne the isue but dont oike the chinese rubbers lol.

Any help appreciated as im sick of putting pull cords in this POS from my son non stop having to start it.

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[BuckthornBonnie]

My son has a POS ms 250 that is really starting to piss me off. That was my rant lol

Ok so i presure tested it a bit ago and it did have a little leak where the lower end of the motor bilts of. Fixed that and no leaks.
It has alway been a finicky saw for idleing.
Put a carb kit in oem carb while back and still no better. Tried an aftermarket carb and still no better.

So i have always had this feeling that its something to do with the coil. It runs perfect WOT and come down to idle fine then couple seconds later it either will stumble and continue to run or just shut off. Even if it continues to run after it stumbles it will donit again. Anyone else have any ideas to tro.

Fuel lune does not leak. It is original
I do have a chinese one i could try if anyone thinks that may ne the isue but dont oike the chinese rubbers lol.

Any help appreciated as im sick of putting pull cords in this POS from my son non stop having to start it.

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Did it have the exact same running problems with the different carb? If so, you’ve narrowed it down a bit. The clamshell leak concerns me. How’d you solve that?
Ditch the Chinese fuel line unless you’re just going for a diagnosis. Fuel filter? Air filter look good? Any wiggle to the crank?

 

[merc_man]

I just had the motor out. Replaced the crank seals while it was apart. Reinstalled. No leaks. If i do put chinese line in it will just be to test it the then order new if good.
Ran same with both carbs.
Air filter is good. Idles same if i take filter off too.



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[gduvic]

Piston may be worn out(i.e. to thin on the intake side skirt). I have fixed several saws that have had idleing issues by replacing the piston.

 

[merc_man]

Piston may be worn out(i.e. to thin on the intake side skirt). I have fixed several saws that have had idleing issues by replacing the piston.

If thats the case i think i will use it as a wheel chulk.

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[Wood Doctor]

Have you measured the engine's compression in any way? If you have no gauge, hold the saw with the pull cord handle only and then let it drop with its own weight. If if falls, the compression is gone and you need a top end rebuild.

 

[merc_man]

Have you measured the engine's compression in any way? If you have no gauge, hold the saw with the pull cord handle only and then let it drop with its own weight. If if falls, the compression is gone and you need a top end rebuild.

It was around 150 if i recall rite.
Plenty off life left. I can recheck to be shure once i get some more starter rope.

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[Carhartt]

I am having the same problem with an 026. I don't know what part to throw at it next. I am down to coil and piston.
I have a couple leaking seal 025's on the shelf waiting for the right day. I like a good running 025\250.

 

[Finnrpm]

For that 250 i would try walbro WT-215 carb. Have changed couple 250 with zama carbs to walbro and those have been running good after change.

Noticed while back that some 025 intakes have same " lip " as 026 intakes. That usually causes crappy idling behaviour.....
More of that here -> https://opeforum.com/threads/the-possible-factory-issue-with-026s.6454/

RV

 

[huskyboy]

This is gonna sound really stupid... but have you changed the plug?

 

[Carhartt]

Finn,
Thank you for the link up. I am going to check that. That sounds like it might be my problem and something to keep an eye out for in the future.