Chain saws can be quite an investment and an important tool when cutting out trees and preparing firewood. It is important that this piece of equipment is in good working condition when using. By not repairing problems or maintaining these tools it could lead to very costly repairs, replacements or even severe injuries. It is important to make sure that any replacement parts are for the specified piece of equipment are those suggested by the manufacturer.
Step 1. Adjusting the mixture and idle speed of the chain saw can help to make it run more efficiently. To do this, first make sure that it is turned off. Remove the air cartridge and air filter to get to the idle mixture screw. Turn the idle mixture screws 1 1/2 turns counterclockwise. Locate the main jet adjustment screw with the use of the owner's manual that is specific for the model. Turn the main jet adjustment screw until it is touching the seat of the emulsion tube using a clockwise motion. Turn it 1 1/2 turns using a counterclockwise motion. Place the air filter back where it belongs.
Step 2. With a tachometer, gauge the engine speed of the chain saw. If it is an aluminum cylinder engine model it should run at 1750 RPMs. Cast iron cylinder engine models should have a reading of 1200 RPMs. If there is any other tachometer reading than what is suggested for the engine model there is a need to set the idle speed screw to repair this problem.
Step 3. Inspect the choke plate for the chain saw if there is trouble starting. This will be located at the opening of the carburetor's throat area. Starting this piece of equipment can be affected if the choke plate will not close properly or if it is moving freely. To adjust this, dirt and debris must be removed by using a carburetor cleaner and spraying the cleaner into the shaft of the choke and into the venturi.
Step 4. If there are problems with the actual running of the chain saw, this may be a warning that the spark plugs need to be inspected. A wet spark plug can be a sign that there is water in the fuel. To repair this the fuel tank may need to be serviced. If the spark plug is excessively dry this can mean that the fuel filter is clogged and needs to be cleaned or replaced. Using a micrometer caliper the gap in the spark plug must be measured. The right reading should indicate that the spark plug is gapped at.025 of an inch.