I have an old craftsman chainsaw that wouldn't start I rebuilt the carburetor and replaced the fuel lines it is model 358-355161 16" with a walnut 20 carburetor.It now starts and runs great at top speed,but it won't idle I have both idle screws turned out 1 1/2 turns the low speed idle does not seem to respond one way or the other.When I rebuilt the carb. I think there was a small o ring in the low idle adjustment screw,It was damaged and I wasn't sure if it was part of this carb.I checked other walnut carbs I have but they do not have an o ring.I would appreciate any help in getting the chain saw to idle.
Craftsman chainsaw
- Thread starter Bob Ford
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Just go out to your walnut tree and see any of those walnuts will fit but personally I have never seen a Walnut carburetor. Beside most Poulans uses either the Zama or Walbro OEM carburetors.
Thanks for your help
dougand3
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The idle screw is the big phillips head. It should be turned in/CW for higher idle. The 2 smaller screws are the Lo & Hi jets. Lo is always nearest to cyl. 1.5 out/CCW from lightly seated is a good starting point. Maybe you just need the IDLE screw turned CW. Watch the taper on this screw - you'll see IN/CW gives a fatter part of the taper = more open throttle.
Thank you I will try your advice.
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There are a few exceptions to that rule. I have seen the L and H reversed on some models of the Walbro and Zama carburetors.
And on the idle speed screw when present to not to it is too far as you can break the casting. And on the Zama I just installed the idle speed adjustment is CCW to increase the idle speed. So there is always an exception to the rules.
I meant walbro but it came out walnut I should double checked before I submitted.
Thank you Dougand3 I did what you said I turned the idle adjustment enough to keep it running at idle,then fine tuned the low and hi mixture screws then turned the idle adjustment our until the chain wasn't moving.Its running great it is 40 years old but I don't use it much anymore.I run it with a 40 to one oil and gas mixture because it is so old.Again you were a great help!
I would like to say that I was helped by this site,by other mechanics who seem to have a lot more knowledge than the star tech(the nerd) ! I have been a mechanic in HVAC for 45 years.I am an army veteran .I am just learning the small engine repair service,I know I have a lot to learn.I want to thank those who helped me I am 75 years old and I want to learn all I can to help me in the future.As far as star tech you are a loser!!!