1. COOLING. Clean the flywheel cover and engine fins with compressed air and a brush. It is important to keep your saw's engine running cool. Unrestricted air flow is the key.
2. FUEL SYSTEM. Most chain saw engines are small two-stroke cycle engines. This engine design is lighter for easier handling and allows the engine to lube in any position.
A small two-stroke cycle engine usually requires a gas and oil mixture, with the oil in the gas lubricating the engine.
Clean, fresh fuel mixture is important to a small engine's carburetor. In most cases a fuel delivery problem—the most common engine problem—is caused by the operator not draining the tank and running out the last bit of fuel in the carburetor before storage.
3. EXHAUST SYSTEM. The chain saw two-stroke cycle system usually consists of exhaust ports in the engine and a muffler assembly, which is usually equipped with a spark arrester screen.
Many saws have been scrapped because of a dirty exhaust system. Remember: No air out, no air in, or no air at all means no power. Tell-tale signs of a plugged exhaust system are excessive engine smoking and the inability of the engine to reach full rpm. A plugged exhaust system also can make the engine run hot. The spark arrester is usually the first to plug in the exhaust system. To clean it, let the engine cool, remove the muffler body and disassemble the muffler. Look at the exhaust opening in the engine when the muffler is removed. The opening contains carbon that can be removed with a wooden dowel.
4. BAR AND CHAIN MAINTENANCE. The bar and chain work as a team to deliver the power of the engine to the wood. The key to keep them working is to sharpen, keep the correct tension and make sure you have a full chain oil reservoir.
- Sharpening a chain is not difficult, but check your owner's manual or ask at your local farm supply store for sharpening techniques when using a file.
- Chain tension is also important. Adjust chain tension by loosening the guide bar nuts or knob and lengthening the bar by turning the chain tensioning screw (usually clockwise) or wheel.
A cold chain is correctly tensioned when there is no slack on the underside of the guide bar, but it can still be turned by hand without binding. Wear gloves when you move the chain by hand.
The drive tangs of a correctly tensioned warm chain will hang approximately the thickness of a dime below the bottom bar groove.
- Bar oil is recommended to lubricate the bar and chain because it does not easily sling off the end of the bar. Although most saws automatically oil the bar and chain, a flow adjustment is usually provided.
5. AIR INTAKE SYSTEM. Any engine must breathe clean air. Most air filters can be cleaned by tapping, blowing or washing in soapy water. Check your owner's manual on the air filter cleaning procedure for your saw. Be careful when replacing your air filter and cover.
Many saws have been ruined because of a poor seal around the air filter base, which allows unfiltered air to enter the engine. Unfiltered air can quickly "dust" an engine.
6. IGNITION SYSTEM. Newer saws have an electronic ignition. The design significantly lessens ignition problems compared to the conventional points and condenser system.
There is virtually no maintenance on the electronic ignition. If you have no spark, check your switch, wiring and spark plug. Remember to check the spark plug gap according to your owner's manual specifications. Also, check for carbon buildup. The black gunk on the tip of the plug can kill the spark. The spark plug should be changed annually.