Ms271 has me stumped.

RED-85-Z51

RED-85-Z51

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Fixed 11 saws today no problem, but this 271 has me stuck. Saw had 155psi compression cold, piston looked mint. Came in with no muffler so i put one on. Fired right up on fresh fuel..idled alright, little cold natured, when revved it would take off and fall on its face.

New fuel filter, fuel line holds pressure, carb looks fine inside, diaphragm is perfectly pliable, no dirt at all. I turned the needles out 1/4 turn and it will idle 20 minutes no sweat. You rev it, it hits about 13,500 and cuts off...like no fuel.

It got late on me ill hit it again in the morning, ill pressure test the case if needed but usually if there is a problem there it doesn't start easy or the idle is erratic. Im starting to see more and more xx1 series saws now...

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RED-85-Z51

RED-85-Z51

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Tip from the fellows at my favorite Stihl store:

Avoid the models ending with a one.

I have a 311 here now driving me nuts. [emoji2959]

But, it was free. [emoji20]
I put...wayyy too much money in fixing a free 311 in the spring, its a good saw, heavy...but pulls a 25" bar well enough.

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rupedoggy

rupedoggy

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Just random ideas; Partially plugged pulse line. Small screen in carb partially blocked with that gunk you can't see. Pin hole in fuel line or pulse line. one of the connections is a little loose or not quite pushed all the way in. The fulcrum on the needle is a little low. plugged exhaust screen. Old fuel. Spark plug not gapped properly or dirty/carboned.
 
RED-85-Z51

RED-85-Z51

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Just random ideas; Partially plugged pulse line. Small screen in carb partially blocked with that gunk you can't see. Pin hole in fuel line or pulse line. one of the connections is a little loose or not quite pushed all the way in. The fulcrum on the needle is a little low. plugged exhaust screen. Old fuel. Spark plug not gapped properly or dirty/carboned.
Im going to swap a carb off another 271 on...see if that makes a difference. If not ill have to dig into the saw itself.

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Old2stroke

Old2stroke

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How about the fuel pump diaphragm? The teflon ones seem to last forever but the acetate and rubber ones,as they age, may not deliver enough fuel for maximum fuel at high speed.
 
RED-85-Z51

RED-85-Z51

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I pulled the carb back off and it all still looked fine, but i had a kit so i put it in, immediately ran better. It has a bit of a bog in the middle, not right off idle...around 6000 rpms where it bucks just slightly on rev up...but it idles great and holds consistent rpms up top.

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mountainlake

mountainlake

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Most likely the diaphragm was getting stiff not letting enough mix in, adjusting the metering lever just a tad higher most likely would have made it run. Steve
 
RED-85-Z51

RED-85-Z51

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Something to note, in the few hours since i removed it, the diaphragm that was pliable and soft...has dried out and become quite stiff.

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Tobystihl

Tobystihl

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Tip from the fellows at my favorite Stihl store:

Avoid the models ending with a one.

I have a 311 here now driving me nuts. [emoji2959]

But, it was free. [emoji20]
I agree, I avoid wasting any time on the non professional models, lost too many weekends fixing them for very little reward!
 

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