Chainsaws require regularly scheduled maintenance for proper operation. Clean your chainsaw after each use and refer to your owner's manual for information. Follow these troubleshooting guides in the event of starting difficulties.
Make sure you follow specific chainsaw starting procedures. This typically looks like depressing a decompression valve, pressing and pumping the priming bulb, closing the choke, and pulling the cable to start. There may not be anything wrong with the saw and may simply have an open choke, throttle, or decompression valve.
With every gas engine, three important ingredients are necessary for operation: air, fuel, and spark. In a chainsaw, the ambient air is pulled into the carburetor through an air filter. Gasoline (mixed with oil) is pulled into the carburetor by vacuum from the fuel tank. The spark plug creates a spark as the engine turns over and pulses the ignition module. When the saw refuses to start, your issue lies in one of these systems.
Even so, your chainsaw may need a refresh and tuning to keep it running smoothly. Follow this guide to keep your saw running and prevent overheating. It's important to assess what part of your saw is overheating and where it's smoking from.
Dirty Air Filter (air)
Black smoke, or white and blue smoke after 10 minutes suggests an engine problem behind the smoke. First, let your saw cool down, and check the air filter. The air filter feeds your carburetor with clean, ambient air. If your air filter is full of oil or sawdust, you can try spraying with compressed air or washing with soap and water. In the event your filter is too destroyed, replace the filter completely.
Sawdust in Cooling Fins (air)
We know sawdust is flammable, so when it accumulates near the exhaust of the saw, it can combust and cause smoke. Clean off the cooling fins and remove wood from under the bar cover.
Clogged Spark-Arrestor Screen (air)
Running too rich over time can clog the metal screen in the exhaust. Remove and inspect the screen. Put the screen into a vise, and use a torch to heat and burn all of the carbon on the screen until it becomes ash. Use a wire brush to remove the ash, then replace.
Oil and Fuel Mixture Incorrect (fuel)
When mixing the fuel and oil ratio, adding too much oil will result in white smoke from the exhaust. Adding more gasoline to your mixture should clear the smoke.
However, if you notice an overheating saw, try adding more oil to your fuel mix. Failure to add any oil to the fuel mix will cause destruction of the engine.
Chain Teeth Aren't Sharp (chain)
With use, the chain's teeth need to be resharpened. Dull teeth are evident in the dust produced from cutting instead of chips, and from a hot chain and bar. Grab a round file of appropriate diameter and sharpen the chain.
Tree is Too Big (wood)
Overloading or running your saw continuously for too long is likely to overheat your saw's motor. Let it rest for 30 minutes, then continue.
Running Too Lean (air+fuel)
Your carburetor needs period adjustment based on seasonal temperatures, or after so many hours of use. Smoking is an indication that your carburetor isn't getting enough fuel and too much air. This condition is dangerous for your engine because overheating can cause the piston rings to fail and self-destruct. Turn the H screw out counterclockwise while the saw is running at max throttle until the RPM drops, then turn back slightly. This will make the fuel mixture more rich.
Idling Too Fast (air+fuel)
When smoke is coming from the exhaust while the chainsaw is idling, the L screw needs adjusting. Turn the screw counterclockwise until you hear the RPM drop and smoke stop. Verify with factory specifications.
No Oil in Tank (oil)
The oiler dispenses oil on the chain and bar and keeps the chain lubricated and cool. If the oil reservoir is empty, the bar and chain will become increasingly hot. Add oil, and allow the saw to cool down.
Oiler Not Working (oil)
Sawdust, dirt, and other particulates can clog the filter to the oiler. Verify that the filter isn't clogged, and replace or clean if necessary.
Sawdust may also clog the oiler where it dispenses fluid. Remove the bar guide and clear any foreign materials away from the oiler orifice
Clogged Exhaust Port
It your saw is stored in a dirty place and exposed to dust and debris, the exhaust port may become clogged. This is more noticeable if you regular use the saw because the sound coming out of the exhaust will sound different.
Chain Worn Out (chain)
After many cycles of sharpening and dulling, or hitting an object like a rock, it's possible the chain is too worn out to continue cutting. In this case, replace the chain. However, with normal use the chain teeth dull and rakers need adjusting.
Chain Rakers Too Long (chain)
When the raker, which alternates with teeth on a chain, is higher than the tooth tooth, it can be a source of inefficient cutting and heat buildup. To fix this, file the raker with raker gage or by eye to a lower level than the teeth.
Chain Too Tight (chain)
A chain that's too tight can put undue stress on the motor and cause it to overwork. Loosen the chain slightly, and tighten the nuts.
Chain Too Loose (chain)
A chain that is too loose may be slipping and cutting inefficiently, building up heat in the bar and chain. Increase the tension, and tighten the nuts.
Carburetor Screw Adjustment by Craig Kirk