Posted by John W S son of John S [162.158.126.55] on Friday, April 21, 2017 at 13:25:34 :
In Reply to: Re: Reviving my 45 year old Stihl posted by pw58 [108.162.216.55] on Friday, April 21, 2017 at 07:50:34 :
An air leak from a seal, blown gasket, cracked hose, etc. will cause a saw to run lean. This condition normally shows up as hard starting and erratic idling. They can be difficult to track down if they are small, but the symptom is the idle speed will pick up and drop off without turning the low end adjusting screw much or at all. I can best describe it as the adjustment not really wanting to stay put. It is also likely that it will seem to run fine on the high end but running lean is not good.
A good pressure / vacuum test on the saw will show any leaks, but I doubt that many have the block off plates required. On an 044 the seals are not hard to change and do not require splitting the case.
Running only on choke, even on the high end sounds like a fuel delivery issue to me. I would check out the filter and the fuel pump side of the carb for dirt.
John S.
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