Stihl MS271 high revs then stalls

[M4cc4s]

Hi, i'm having trouble with my Stihl MS271, i can start it up with the choke half open but it revs like mad, then when i give it some throttle it stalls unless i really rev it up, but even then it stalls after a while.
I've cleaned the carb out, flushed the fuel lines through, changed the spark, cleaned the air and fuel filter, checked the compression.
Any help greatly appreciated

[pleasant]

When you say 'checked the compression' what is the cold reading in psi?

[Stubby]

1 hour ago, M4cc4s said:

Hi, i'm having trouble with my Stihl MS271, i can start it up with the choke half open but it revs like mad, then when i give it some throttle it stalls unless i really rev it up, but even then it stalls after a while.
I've cleaned the carb out, flushed the fuel lines through, changed the spark, cleaned the air and fuel filter, checked the compression.
Any help greatly appreciated

I think you have a fuel related problem . I know you have looked at that Re the carb and fuel lines but maybe dig a little deeper . Maybe the gauze filter in the carb ?

[Dan Maynard]

Air leak? If it needs half choke to start then over revs.

[Stubby]

10 minutes ago, Dan Maynard said:

Air leak? If it needs half choke to start then over revs.

 ?

[spudulike]

So....your description, is this from cold or hot? 

I ask this as from what I think you are saying, when using the "Half choke" which is the "Fast idle" setting that gives partial choke and kicks the throttle open a little, the saw revs at a higher rate than it should.

So...the faster than normal revving could be the "Fast idle" mechanism not working right, an air leak or the carb offering an overly lean mix at idle.

The stalling on idle could also be contributed to the above.

When the saw is idling, does it idle faster than it normally does?

Has anyone cocked around with the carb settings to try to make it work better? 

Were the exact same faults present before you worked on the saw? Just making sure you haven't put something back together incorrectly!

[M4cc4s]

15 hours ago, Stubby said:

I think you have a fuel related problem . I know you have looked at that Re the carb and fuel lines but maybe dig a little deeper . Maybe the gauze filter in the carb ?

yep i stripped the carb down and flushed through with cleaner including the gauze, thanks

[M4cc4s]

14 hours ago, spudulike said:

So....your description, is this from cold or hot? 

I ask this as from what I think you are saying, when using the "Half choke" which is the "Fast idle" setting that gives partial choke and kicks the throttle open a little, the saw revs at a higher rate than it should.

So...the faster than normal revving could be the "Fast idle" mechanism not working right, an air leak or the carb offering an overly lean mix at idle.

The stalling on idle could also be contributed to the above.

When the saw is idling, does it idle faster than it normally does?

Has anyone cocked around with the carb settings to try to make it work better? 

Were the exact same faults present before you worked on the saw? Just making sure you haven't put something back together incorrectly!

it doesn't idle, it stalls if i don't continue giving it lots of gas, i've reset the carb settings to factory.

The problem started occuring before i begun work on it

[M4cc4s]

Just now, M4cc4s said:

it doesn't idle, it stalls if i don't continue giving it lots of gas, i've reset the carb settings to factory.

The problem started occuring before i begun work on it

even when its hot i can only start it with the choke full initially

[M4cc4s]

15 hours ago, Dan Maynard said:

Air leak? If it needs half choke to start then over revs.

thanks, so am i looking around where the carb is seated