Stihl 201T high idle even w/idol screw fully backed out

Dead Cottonwood

Dead Cottonwood

Location
Wasatch Front
Had a 201T for over 10 years w/no issues. Recently it kept dying while idling even after carb adjustment. Cleaned the carb but still doing the same thing. This saw has been ran hard for over a decade and owes me nothing but would like other’s opinion on if it’s fixable or if it needs to be rebuilt. Thank you in advance for any assistance.
 
I suspect you have an air leak. First thing I would check, since you said you cleaned the carb is to see if there is any left over paper gasket between the carb manifold and the cylinder. Common problem and missed quite often. If that is all cleaned off properly, I would then look for a crank case air leak. But I am betting there are some shards of paper gasket left on the cylinder from the old gasket that are letting air in at that location.
 
Shadowscape said:
I suspect you have an air leak. First thing I would check, since you said you cleaned the carb is to see if there is any left over paper gasket between the carb manifold and the cylinder. Common problem and missed quite often. If that is all cleaned off properly, I would then look for a crank case air leak. But I am betting there are some shards of paper gasket left on the cylinder from the old gasket that are letting air in at that location.
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Thank you. I will look into this tomorrow
 
Odds are it's a maintenance fix like a cracked/aged hose, I believe the saw has a flex carb coupling and/or the crank seals just wore out or hardened up with age. Get/borrow a hand vac/pressure pump, an adapter plate to put where you take the carb off, a piece of inner tube to clamp between the muffler and the cylinder and do vac/pressure leakage testing. On pressure you can use soapy water for bubbles like finding the leak in a bicycle tire.

Just to rule it out also do a compression test. You could have worn it out.
 
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It’s an air leak or a carb. Can’t think of what else it would be. A 10 year old carb has had a great run, did you do a full tear down when you cleaned it?
 
dug a little deeper in the saw and found no signs of cracked hoses, seals, and gaskets. Looking like I’m just going to buy a new saw while I break this one down further. Thank you all for your input and assistance.
 
There will be no visual indications of leakage except gross hose cracking. Gaskets and seals are are indicated by leak down and identified separately. If you tear it down you lose the chance to prove - you had leakage - you had no leakage and no teardown is required. Absolve fuel/carburation or find out carb is the only remaining culprit. For learning fun search up the Stihl factory tech diagnostic procedure and follow it - free, worthwhile edumacation.
 
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