Replacement should be a last resort in my book. If you cannot tune it for these conditions, rebuild the carb. The end result should be idling without stalling, clutch disengaged, acceleration to high speed without stall or bog, max power in the cut. You might have to raise the idle speed screw some. Repeat this idle process, lowering the speed screw each time until you get the clutch to disengage and the engine idling smoothly.Ĭheck for acceleration lag when opening the throttle, if there is a lag, turn the idle mixture screw out a little and try again.

Adjust it for max speed and lower the idle speed screw some more. The engine should sound a little rough when it is right and smooth out when you put a load on it by cutting.Īfter the high speed is set close, lower the idle speed screw until the idle mixture screw has an effect. Adjust the high speed mix for good running, a little slower/richer than maximum speed. Then start it up and set the idle speed screw high enough so it will run without stalling. If it runs ok, leave it alone, if it has carb trouble, rebuild is cheaper and you learn more.Ĭheck the fuel line all the way to the pickup/filter in the tank, make sure there are no leaks. Put the bar and chain on and see how it cuts. Try this, the carb adjustment procedure I use, posted a few days ago