Stihl MS 271 (carburetor) help

[kenbahn]

i got a stihl MS 271 that has ran great (~60 hours) for me since buying it used from a dealer. Just days ago in the middle of cutting a ~3' ash on the ground for firewood, the saw bogged and shut down. I'm having a difficult time getting it going again. The carb is hard to identify and remove - haven't yet! Got it running on starter ether and made adjustments and now it runs with the L idle set super rich and cut nice for an hour. If i back out the L much more than a full turn, the saw shuts down. I did twiddle the other adjustments and definitely amateur mechanic here.
Seems the carb is clogged and not reliably delivering fuel via the L port? Runs good at high idle and seems a bit gutless in the cut, but it worked nice.
Then played with adjustments more, and saw idles Low nice super rich, and wants to shut down when i start to squeeze the throttle; though if i feather throttle thru the low-mid RPMs it runs up pretty good (and half gutless).
So, any simple advice on how to actually get to and remove and clean the carburetor?
Or an advice on how to set up the carb to make it happen?
thanks.
ben.

 

[brad ruch]

Pm me your email.i will send ya the service manual.

Sent from my SM-G930V using Tapatalk

 

[brad ruch]

Sounds like its lacking fuel.could be a number of things. Dirty carb cracked fuel line.

Sent from my SM-G930V using Tapatalk

 

[kenbahn]

okay. yeah, i wanna clean up the carb.

 

[HarleyT]

Not familiar with the saw, but here is the blowup.

 

[kenbahn]

the carb "floats" in that plastic assembly. guess i could have asked more specifically, how to get the carb out of there. anybody gimme quick advice on how to remove the carb without blowing up all the plastic bits.
thanks for the diagrams y'alls.

 

[backhoelover]

sounds like you have a air leak also. pressure and vac testing time

 

[kenbahn]

pressure and vac testing: does that mean get a compression tester? and attach to both the spark hole port and wouldn't i want to on the fuel intake too? thank you.
also, let me complete the details that i can feather the saw up to high speed, and ran it almost an hour making cuts, though a bit gutless, it ran wide open and made nice cuts thru the big trunk.
thanks again everybody.

 

[backhoelover]

here is the manual. just read it will help you in the repair. also shows you how to do a pressure and vac test. also could have a bad tank vent that is in the manual also. along with carb adjusting, just a process of elimination

 

[kenbahn]

alright, still stuck on item 12.2 in the manual: removing the air filter baffle. i'm not sure what size socket or driver to use to remove those tiny nuts. the parts list calls them M5 and they are not specified in the "how to service" manual. so they 5 mm i need a skinner driver tool to get in there? i'm going to town tomorrow so could get something since none of my sockets or other drivers fit.
anybody tell me exactly what to get? thanks

 

[brad ruch]

5mm is 5 millimeter.all harware you will need metric allen wrenchs and sockets.lol

 

[kenbahn]

i get that Mr Ruch. is it some special super thin wall long 5 mm socket that reaches into the filter baffle plastic thing to pull the M5 (as specified in the manual) nut? my 1/4" metric sockets don't fit into the plastic housing for the air filter mount baffle dealy.

 

[brad ruch]

Pressure vacuum test you will need a mightyvac 8500 or equivalent. I just bought mine on ebay 58.99 there are a couple other kits on there for like 100.00 comes with everything you will need.
-Pump-Kit-/322207297958?nav=SEARCH
-Pump-Kit-/322207297958?nav=SEARCH

 

[brad ruch]

That im not sure of.take a cheap 5mm socket and grind the outside down to fit.ive done that before and still use it.

 

[kenbahn]

sure, but can i expect to find some skinny thin wall deep 5 mm socket or driver at the parts shop tomorrow to pull that M5 nut off the air filter housing baffle?

 

[kenbahn]

right on. thanks

 

[brad ruch]

Invest in a compression tester also.yoy dont need no 100 one.i think i paid like 30 or 40 for .mine.these extra testers are money well spent and take alot of guess work out.

 

[backhoelover]

That 5m I don't think is the socket size it's the thread size I'll check manual when I get home

 

[backhoelover]

If there is a socket what is the part number?

 

[HarleyT]

It is just the same old carb nut, just use a regular 5/16 nut driver, or 8mm, if you insist. If it is too thick to get in there, just take it to a handy bench grinder....