MS180 Stihl carburetor issues

[Bone]

I have an MS 180 Stihl and from day one it never really idled properly. I used it infrequently the first year and the warranty period came and went. I would have to keep the throttle depressed a bit or goose it frequently to keep it from stalling and the idle adjustment did nothing. I replaced the fuel line and filter just in case they were bad but no change. I bought an after market carb and put it on and it had the same problem, perhaps worse, and again, the idle adjustment did nothing. I next put on a rebuilt OEM carb and it worked great for a while but now has issues of not getting fuel through after I use up a tank of gas and the saw is hot. It restarts OK after it cools down and sits for a while. So I put back on one of the other carbs because it at least runs and will restart when hot but I can never get it up to full power and it has the idle issue. I assume the quality control on these is bad and there is nothing to be done with a carb that was made out of spec. I have rebuilt all these a number of times with new diaphragms and kits and cleaned the carbs thoroughly but I can tell this is not the problem. I suppose I should buy a new OEM carb and hope for the best. The saw is great when it is running up to snuff. Any suggestions?

 

[Thommo]

Check your muffler screen. They can clog up and cause running issues that seem like a carb problem.

 

[Chris-PA]

but now has issues of not getting fuel through after I use up a tank of gas and the saw is hot. It restarts OK after it cools down and sits for a while.

Sounds like the vapor lock I deal with: http://www.arboristsite.com/community/threads/hot-starting-vapor-lock-issues-e10.262628/

 

[weimedog]

Have to drag out old war stories from time to time for a re-run.
( chainsawwhisperer can verify all this as he's the guilty culprit )
At one of our early GTG's... that's a few years back now... some typical CAD horse trading went on. I ended up with this new looking MS170. Figured HOW could I go wrong! And what a deal it was. Looked out of the box new. Person I traded for it said it might need a carb or something along those lines and it never ran well. SO I took the challenge.

Spend countless hours trying to make that saw run. I'm certain has Jim seen the efforts he would have smiled as I suspect he also had put time into that saw. AFTER putting another carb and yet another ignition on the thing, completely ignoring my instincts .. and having already done what I thought would have solved its issue...tank vent/caps etc...I decided once and for all to tear it down to atoms if necessary to figure it out.

Took off the carb...yet again...but this time with a different frame of mind, and noticed it was missing something.

No pulse hole on the case side.

Must have came that way from the factory. SO a drill and leaving a little "dust" for punishment later...I had a perfectly running little Stihl which I promptly sold to my Ferrier. Who has used it for several years now trimming motorcycle trails on my farm.

 

[HarleyT]

Ferrier?

Is that like a Labradoodle?

Or is that a horse/hoof guy that drives a real expensive car?

 

[Chris-PA]

Is that like a Labradoodle?

No, those are Porch dogs.

 

[Bone]

Have to drag out old war stories from time to time for a re-run.
( chainsawwhisperer can verify all this as he's the guilty culprit )
At one of our early GTG's... that's a few years back now... some typical CAD horse trading went on. I ended up with this new looking MS170. Figured HOW could I go wrong! And what a deal it was. Looked out of the box new. Person I traded for it said it might need a carb or something along those lines and it never ran well. SO I took the challenge.

Spend countless hours trying to make that saw run. I'm certain has Jim seen the efforts he would have smiled as I suspect he also had put time into that saw. AFTER putting another carb and yet another ignition on the thing, completely ignoring my instincts .. and having already done what I thought would have solved its issue...tank vent/caps etc...I decided once and for all to tear it down to atoms if necessary to figure it out.

Took off the carb...yet again...but this time with a different frame of mind, and noticed it was missing something.

No pulse hole on the case side.

Must have came that way from the factory. SO a drill and leaving a little "dust" for punishment later...I had a perfectly running little Stihl which I promptly sold to my Ferrier. Who has used it for several years now trimming motorcycle trails on my farm.

 

[Bone]

I can relate to the countless hours trying to make the saw run. I'm an expert at quick disconnect and reconnect carbs on the 180. Maybe there's a Guiness record competition for this sort of thing. Anyway, which one is the " pulse hole on the case side"?? I'm convinced there is something wrong with these carbs and won't be surprised if there is a machining problem with them.

 

[Bone]

Check your muffler screen. They can clog up and cause running issues that seem like a carb problem.

Thanks. Screen is clean.

 

[94BULLITT]

My 170 would not idle long with the stock carb on it. I put a WT215 on it and it will idle all day now. Did you get a cheap aftermarket carb? Does it have a high and low adjustment? Have you played with the L adjustment?