To troubleshoot a Craftsman lawn mower, you must first identify the specific problem. Some common problems with Craftsman lawn mowers are dirty blades, low oil levels, broken overrunning clutch or gear, bad spark plugs and a dirty carburetor.
If you are unable to pull the cord to start the mower’s engine, check if there is any grass stuck between the blades. With the mower turned off and the spark plug wire disengaged, remove any excessive clippings from the blades.
If you can pull the cord but the engine does not start, is hard to start or does not stay started, check the tank’s oil to ensure there is enough. For an electric starter, check the battery.
If the motor spins but does not engage the engine, check whether the overrunning clutch or gear is broken. If either of these is broken, seek professional help.
For an engine that starts easily but does not stay started, prime it correctly. Too much priming may flood the engine.
Damaged spark plugs may make an engine hard to start, run roughly or quickly die out. Examine your lawn mower's spark plugs, and if they appear worn or damaged, replace them.
For an engine that idles roughly or unevenly, clean the carburetor using a rag or towel. If your carburetor is clean, contact a technician to check for improper adjustment or air leaks.