My Craftsman 3.3 Chainsaw Won't Idle

Loss of Idling

• The loss of idling occurs from a loss in air or fuel. The carburetor must suck fuel in from the tank, measure it for the current engine speed and mix that fuel with the proper amount of air for combustion in the cylinder. Most fuel shortages are caused through a loss in fuel arriving into the carburetor. These losses occur most often in the tank, in a dirty fuel filter, in clogged fuel lines and in dirty jets on the carburetor. A dirty air filter causes a drop in air for mixing.

Carburetor Adjustment

• A simple tweak in the carburetor's screws will generally solve most idling problems. This will adjust the screws controlling the inlet needle, the inlet lever and the intake jet. These screws control the high, low and idle speeds of the engine. With poor idling problems, generally the idle and low screws will need to be reset.

  While the engine is at running temperature, screw the idle speed in clockwise until the idle speeds up and the chain starts moving. Slowly back off the screw counterclockwise until the chain stops moving. Try to locate the highest idle speed before the chain starts moving.

Before Making Adjustments

• Before adjusting any carburetor, the fuel and air systems need a thorough cleaning, especially if more than 50 operational hours have passed since its last maintenance. Take the air filter out of the engine and wash it in soapy water, rinsing it out under cool water. Let the filter air dry completely. Drain any fuel leftover in the tank or that has sat in the tank for more than one week. Replace the fuel filter and fuel hoses if more than 50 operational hours have passed since their last replacement.

Adjustment Warnings

• If done poorly, carburetor adjustments can destroy a perfectly good engine in a matter of minutes. For this reason, make only small minor adjustments to the carburetor screws: generally, only 1/8 to 1/4 of a turn is needed to adjust the carburetor properly. Always adjust slowly and never move the screws past their maximum lean settings. Never adjust the idle speed so high that the clutch stays engaged and the chain continues spinning. While adjusting the idle speed, keep the chain free of any obstructions because it will move.