Stihl ms250 fuel issues

[Lee H]

So i inherited this MS250 from my elderly neighbor. He had trouble getting it started. He took it to the Stihl
dealer and they put a new carb on it. It would run but never ran right. He gave it to me. Been sitting in my shed
for about 6 years. I dragged it out and put fuel in it and primed it down the carb and i fired but wouldn't pull fuel. I quickly noticed the fuel line was all cracked. I replaced fuel line, pulse line, intake boot and a carb kit with all oem parts. It runs now but will not idle and bogs when you hit the throttle and dies. It will rev up nice
and 4 stroke but just not getting enough fuel through the low side. It has a Walbro WT283c carb. Has anyone had issues with these and is it the correct carb for this saw. I have had the carb apart a couple times and sprayed carb cleaner through all the holes and nothing seems to be plugged. It has a fixed high jet.

Thanks for any help.

 

[jacob j.]

Sounds like the same issue I had with my mom's MS-210 Lee - It had the semi-fixed jet carb and sat for a year with fuel in it. I put a new fuel line, filter, carb kit, and tank vent on it and it wouldn't pull enough
fuel through the low circuit. I ended up replacing the carb and it runs perfectly.

I'm not sure if the WT-283 is the correct carb for the 250 as most of those I've worked on came with the WT-215. I suspect it's probably right though as the IPL lists the WT-286 as an alternate carb. Replacing the fuel line is a good first move on those as the fuel lines have a lot of problems where they exit the tank and make the bend into the airbox.

There's also a Zama carb available for those - C1Q-S75 that might be a better carb for your application.

 

[Canadian farm boy]

I’ve had several of the ms250 come my way with similar running issues. So far they’ve each been repaired with an echo style tank vent, carb kit and adjusting the carb pop off pressure.
The ones I’ve seen have had a pop off pressure of over 30psi. (That’s as high as my mytivac gauge reads) I just snip coils off metering lever spring until I get it around 20psi.

 

[Steve]

Does it have the accelerator pump under the throttle shaft? My ms250 did the same thing as yours and I replaced all the same parts as you did Lee. Found the accelerator pump plunger was stuck depressed. Took the throttle shaft out to free it up. Ran great untill it stuck again. Replaced the carb and it's been fine since. That was 5 years ago.

 

[FergusonTO35]

Hmm, lots of good information here!

 

[Lee H]

Does it have the accelerator pump under the throttle shaft? My ms250 did the same thing as yours and I replaced all the same parts as you did Lee. Found the accelerator pump plunger was stuck depressed. Took the throttle shaft out to free it up. Ran great untill it stuck again. Replaced the carb and it's been fine since. That was 5 years ago.

Never knew they had an accelerator pump. Do you remember what carb you had on it.

 

[Lee H]

Ok so if i do a carb replacement what are my options. Are the aftermarkets any good, I think i know
the answer to that. If i go OEM which carb would be the best choice.

 

[Steve]

Never knew they had an accelerator pump. Do you remember what carb you had on it.

I believe it was the Zama. Was 35 bucks at the Stihl dealer. I just asked for a carb for a ms250 and that is what I got.

 

[Woodslasher]

I believe it was the Zama. Was 35 bucks at the Stihl dealer. I just asked for a carb for a ms250 and that is what I got.

My 250 came with a Zama and got a replacement Zama put on it (rotted diaphragms/fuel line), I've never had an issue with it. It always starts, never dies, and has none of the "common issues" that other 250's have.

 

[Squareground3691]

Helps to do a muffler mod on 250’s , to restrictive

 

[Squareground3691]

Helps to do a muffler mod on 250’s , to restrictive

Extra port on top

 

[Lee H]

So i went ahead and bought a new oem Stihl carb #1123 120 0605 which is the WT-215 carb with both HI and LOW
adjustments and it runs perfect. Idles, Revs, cuts, i'm very happy with it. Got this saw a few years ago and it's going
to nice lady friend of mine. I think it will suit her very well.

Thanks for all the help guys.