064 running funny

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Patrick62

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Ran 1 1/2 tanks today on the 064IMG_0683.jpg
I fetched out the adjustment screw driver, and twiddled it. Eventually I learned something...
I was trying to adjust the idle down, it was idling just way to fast to suit me, and the chain would not stop...
Ok, played with the L setting, and eventually backed the idle screw all the way loose. still rapped up.
I will check out the carburetor closely... it is a china knockoff of the fine Walbro that should be in there, but it worked fine for a year or two...
It has to be the carb... but I fully intend to pressure/vacuum test this saw. Just to be certain that the seals are good.

Logically, if it is running, then the butterfly has to be open enough to pull fuel from the carb... evidently the idle screw did NOT allow the throttle plate to close completely.
Or the saw would have died... which is what I expected it to do.

Strange?

Have you seen this before?
 
I've seen simple things like a bent linkage or crud around some part of the throttle mechanism prevent it returning all the way.
Can do a reasonable leak check with a can of WD-40 or similar (with the straw) & with the saw running spray around any potential leaks. Be sure to shield the intake from any spray or you'll be chasing non existent issues
 
If the saw is running at a faster idle than it normally does, don't get distracted by clutch issues that aren't relevant. Check obvious things first, something is probably preventing the throttle from closing right down to the idle position, sticking throttle? Bent linkage? Nothing obvious, then start looking for slight air leak that would lean out the idle mix.
When it's idling too fast does it slow down if you back out the low speed mixture screw?
 
I have a vac/press tester here, I will do it the right way... the wd40 is a cool idea tho.
clutch springs are probably a little loose, but it used to idle down quite nicely...
took the carb off, and a 10 second look down the bore, the throttle plate is NOT seating down to closed for some odd reason. Other tasks demanded attention. so I could not work on it then.

old2stroke, re-read the post... I backed the idle screw out about 6 complete turns. no change.
The saw should have stalled....
 
Even with the idle screw all the way backed off, there is usually just enough gap to draw fuel, especially if there is some other air leak.

So unless you find some physical blockage of the throttle plate/linkage etc then its more then likely a bad seal somewhere, most likely on the clutch side, especially if you've gotten the clutch nice and warm say a pinched chain or a very dull chain etc.
 
Ran 1 1/2 tanks today on the 064View attachment 973942
I fetched out the adjustment screw driver, and twiddled it. Eventually I learned something...
I was trying to adjust the idle down, it was idling just way to fast to suit me, and the chain would not stop...
Ok, played with the L setting, and eventually backed the idle screw all the way loose. still rapped up.
I will check out the carburetor closely... it is a china knockoff of the fine Walbro that should be in there, but it worked fine for a year or two...
It has to be the carb... but I fully intend to pressure/vacuum test this saw. Just to be certain that the seals are good.

Logically, if it is running, then the butterfly has to be open enough to pull fuel from the carb... evidently the idle screw did NOT allow the throttle plate to close completely.
Or the saw would have died... which is what I expected it to do.

Strange?

Have you seen this before?
Could the inlet control lever in the carburetor be holding the needle open due to being bent at the wrong angle?
 

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