Homelite chainsaws have a two-cycle engine. This type of engine mixes gasoline and oil directly in the fuel tank. The mixture is used not only for fuel, but also to lubricate the internal parts of the engine. The coil, which is connected to the side of the engine block, is what creates the electricity, or spark, sent to the engine by way of the spark plug. Spark from the plug ignites the the fuel mixture in the cylinder of the engine, causing combustion. When a coil overheats or malfunctions, the chainsaw will no longer start. You can troubleshoot the coil in a few short steps.
Place the chainsaw on a flat surface. Remove the ignition switch. It is located to the left of the throttle trigger. With the flat head screw driver, pry the switch loose.
Unplug the ignition switch to expose the ignition wire.
Push the jumper wire onto the exposed ignition wire; this will bypass the ignition system. Turn over the engine by pulling on the starting cord. If the engine starts, replace the ignition switch with a new one. If it doesn't start move to the next step.
Pull off the spark plug wire. It's the black wire leading into the spark plug. Hook up the spark tester by plugging one side of the tester into the spark plug wire, and clipping the other side of the tester to the spark plug. Turn the engine over. If there's spark, remove and replace the spark plug. If there's no spark, move to the next step.
Replace the ignition coil. Remove the plastic engine cover held on by hex screws. This will expose the ignition coil. Remove the two nuts holding it down. Install a new coil by reinstalling the two nuts, turned hand tight. Set the gap between the coil and flywheel. Check your service manual for the proper gap setting. Most Homelite saws have a gap setting from .010 inches to .020 inches. If you do not have a gap gauge, a common business card can be used to create the gap.
Place the gap gauge with the proper setting or the business card between the flywheel and coil. Push the coil tightly towards the flywheel. Tighten the screws to the coil and remove the gap gauge or business card.
Reinstall the plastic engine housing. Turn over the engine and test to make sure the engine starts.