QuestionI have an old hand-me-down Craftsman chain saw with now manuals. How do I adjust the carb? It has 3 adjustment screws: idle, low and high. It has a new plug and new air filter. The original problem was bogging down during the cutting (not from binding or deep bytes). I really fixed it. It won't run above an idle.
Thanks.
AnswerI would check the muffler spark arrestor screen, muffler ports and exhaust ports. On older 2 cycle engines these become clogged with carbon and cause poor performance.
As the adjustment, set both high and low needles 1&1/4 to 1&1/2 turns out from a GENTLY seated postion...finger tight. This should get the saw running.
The idle is set just so the saw will idle.
For fine adjustment, let the saw idle and warm-up. Turn the low speed needle in until the engine RPMs decrease; the saw should almost stop running. Quickly turn the low needle out to keep the saw running. Keep turning out until the RPMs decrease again. Quickly turn the needle to the mid point of these 2 settings and you should be done.
Do the same thing with the high speed needle, except you will have the saw running wide open. In until RPMs decrease, out until they decrease then find the mid point. I usually turn the high needle out just a little once I find the mid point setting. This will help the saw once it's cutting.
Let me know what happens.
Eric
