If you use your Poulan chain saw regularly, it's important to perform regular tuneups to keep it running well. The procedure includes routine maintenance tasks -- such as checking and cleaning the spark plug, air filter and fuel filter -- and it may also involve adjusting the carburetor. The carburetor is factory preset, but it can fall out of adjustment for several reasons. Depending on your model, you may need a special tool to adjust it.
Spark Plug Maintenance
To remove the spark plug, place the saw on a flat surface; pull off the boot and unscrew the plug with a spark plug wrench. Inspect the terminals for information about the engine performance. Excessive erosion means the engine is running hot, probably because the carburetor mixture is too lean. Carbon or oil deposits mean that engine combustion is incomplete, which can occur because of insufficient air or a carburetor setting that's too rich. Spark plugs are inexpensive, and it's usually easier to replace a fouled one than to try to clean it. Screw in the plug, but don't attach the boot until you have checked all the filters.
Checking and Cleaning the Filters
The air filter is located under the cover on the top of the engine -- to remove it, you must unscrew three screws with a No. 27 torx screwdriver. Clean the filter by brushing it off or washing it with soap and water; replace it if it's too dirty to clean. The fuel filter is located in the gas tank; retrieve it with a hook made with 14-gauge wire, and replace it if it's noticeably soiled. The spark arrestor is behind the muffler and should be cleaned after every 25 hours of use. Unsnap the muffler cover on the front of the engine; pull off the muffler diffuser and spark arrestor, and clean the spark arrestor with a small wire brush.
Preparing to Adjust the Carburetor
You should adjust the carburetor only after you've cleaned or replaced the air filter and spark arrestor. You'll need to reattach the spark plug boot for this procedure, but leave the engine cover off for better access to the adjustment screws. These are located next to the handle on the left side of the engine. There are three of them, but two -- the high (H) and low (L) screws -- may be covered with a tamper-proof cover; pull it off to access the screws. The third screw -- the idle (I) screw -- should be visible. If the screws don't have slots for a flat-head screwdriver, you need a spline screwdriver. This tool is available at hardware stores or online.
Carburetor Adjustment Procedure
The manufacturer covers the low- and high-speed screws with a cover for a reason: Misadjusting the carburetor can seriously damage and even ruin the engine. For this reason, you should refrain from adjusting the high-speed screw -- get a Poulan service professional to do it. To adjust the idle, start the saw, and turn the idle screw clockwise to increase the engine speed and counterclockwise to decrease it, stopping at the point when the engine runs smoothly but the chain doesn't move. Engage the throttle and adjust the low-speed screw by turning it clockwise until the engine races, then counterclockwise until it sputters. Set it midway between these points. Stop the saw and replace the tamper-proof cover to complete the tuneup.