What Would Make a Craftsman Lawn Mower Hard to Start?

Fouled Spark Plug

• A spark plug sits embedded part way inside the cylinder, and, when combustion begins, the ignited fuel will leave trace deposits of carbon behind on the electrode tip. If this electrode tip, covered in black carbon deposits, can't fire a high enough voltage charge, the Craftsman lawn mower will be difficult to start. Slowly unhinge the rubber boot on top of the spark plug, verifying that the metal prong isn't blackened, bent or damaged. Replace the spark plug if it is.

Clogged Fuel Filter

• Fuel rushes from the tank into the carburetor, pulsing in response to the crankcase's movement. As the fuel gets sucked into the fuel line, a fuel filter inside the fuel tank prevents dirt and other debris from entering the fuel system. If grass clippings, oil or dirt get sucked into the carburetor, the engine will be difficult to start. If these objects also lodge against the fuel filter in the tank, the engine may start but quickly die as the fuel flow gets shut off. Replace the fuel filter at the beginning of the season.

Broken Recoil Starter

• The recoil starter on the Craftsman mower allows an operator to manually crank the crankshaft fast enough for combustion to begin. As the operator pulls out the starter rope, the rotor also spins the flywheel and the crankshaft. When the engine fires, the operator lets go of the rope and it should retract. However, if the rotor, recoil spring, starter rope or flywheel get damaged, the rope can be either too easy or too difficult to pull, stopping combustion from happening. Replace the starter rope, rotor, starter cover, recoil spring and flywheel if damaged.

Dirty Carburetor

• The internal combustion engine on the Craftsman mowers need a precise amount of fuel at all times to supply enough power to the engine. However, before the fuel can ignite, it needs to mix with air in the carburetor. Dirty carburetors will interrupt the continuous mixing process, producing low levels of combustion. Impurities from the fuel, dirt and oil can cause these starting problems. Disassemble, clean and brush out all carburetor parts.