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MS170 bogs and will not run

benmyers

benmyers

ArboristSite Operative
Joined
Aug 15, 2009
Messages
316
Location
Indiana
I am helping a friend with a Stihl MS170 that will not run right. He had put bar oil in the gas tank. I cleaned all that and cleaned and boiled the carb out, put a rebuild kit it in. It still won't come off idle and rev. It will idle all day, soon as you hit the trigger it just bogs out. I tried bending the fulcrum arm to get a little more fuel and it didn't help. Put a new fuel line and filter, checked tank vent, still doesn't want to run. It has good compression.

I ordered a new carb but is there something I could be missing? Given the fact that it idles fine, I don't think it has an air leak.

Any help is appreciated
 
HarleyT

HarleyT

A-Hole!!
Joined
Dec 6, 2014
Messages
18,770
I am helping a friend with a Stihl MS170 that will not run right. He had put bar oil in the gas tank. I cleaned all that and cleaned and boiled the carb out, put a rebuild kit it in. It still won't come off idle and rev. It will idle all day, soon as you hit the trigger it just bogs out. I tried bending the fulcrum arm to get a little more fuel and it didn't help. Put a new fuel line and filter, checked tank vent, still doesn't want to run. It has good compression.

I ordered a new carb but is there something I could be missing? Given the fact that it idles fine, I don't think it has an air leak.

Any help is appreciated
Remove the carb again and take it apart. Remove that tiny jet with a small screwdriver and clean it all out.
 
MartDalb

MartDalb

ArboristSite Guru
Joined
May 22, 2017
Messages
725
Location
Denmark
just from todays work on an ms181.
It had a weird, non genuine and bad quality fuel filter, so...took carb apart and check the inside of this carb. (see pictures, 1st is before, 2nd is after a cleanup)
It would run, but bog down rather fast, I wonder why......

After a cleanup and a carb kit - runs perfect.
 

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