How to Repair a Chainsaw. Chainsaws are useful tools if you have to cut down trees that may be damaging your home, nuisance trees and trees for firewood. Most have a two-stroke gasoline internal combustion engine. If maintained, chainsaws work wonderfully. But every chainsaw needs to be fixed at some point. Below are some tips on how to repair a chainsaw yourself.
Make your chainsaw run more efficiently by adjusting the idle speed and mixture. Turn off the chainsaw and remove the air filter and the air cartridge to locate the idle mixture screw. Turn in 1 1/2 screws counterclockwise. Turn the main jet adjustment screw clockwise until it touches the seat of the emulsion tube. Then turn it counterclockwise 1 to 1/2 turns. Replace the air filter.
Gauge engine speed with a tachometer. An aluminum-cylinder engine should run at 1750 RPM, and an engine with a cast iron cylinder speed run at 1200 RPM. If the RPMs are any other number, repair your chainsaw by setting the idle speed screw.
Inspect the choke plate at the opening of the carburetor's throat If your chainsaw has trouble starting. If it doesn't close properly or if it moves freely, this could create starting problems. Loosen any grit by spraying carburetor cleaner on the choke's shaft and into the venturi.
Examine the spark plugs to repair running problems. A wet plug may be caused by water in the fuel, so you'll need to service the fuel tank. An excessively dry plug could mean a clogged fuel filter, which can be fixed by servicing the filter. Use a micrometer caliper to make sure the spark plug gap is .025 of an inch.