Pull and clean the Spark Plug



Most of the time simply cleaning the spark plug will solve your lawnmower woes. To do this, disconnect the wire attached to the end of the spark plug. Then using a wrench or a Ratchet/Socket, remove the spark plug. If the spark plug is black or wet looking, you have probably found your problem on why the lawnmower is not starting.

Using fine grit sandpaper, sand the top of the spark plug down to bare metal. Make sure you sand all around the edges of the piece of metal (tab) that sits just above the electrode. Make sure that there is a gap between the metal tab and the electrode. If you still have the lawnmower manual and a feeler gauge you can adjust the gap to the specifications. However, if there is a small gap it is probably sufficient for the spark plug to operate correctly.

Make sure the spark plug is free of dust and dry. Then screw it back into the cylinder and connect back the wire to the end of the spark plug. Then try starting the lawn mower.

Check for Oil

Make sure there is oil in the lawnmower and that it is at the proper level.

Check for Fuel

Make sure there is gas in the lawn mower. If you have old gas in the lawnmower and did not put in a fuel stabilizer at the end of the season, replace the gas. If you had drained the gas tank at the end of the previous season, then fill the tank at least half full with new gas.

Check the Fuel Line

Like many of us, at the end of the previous lawn mowing season we turn off the fuel line switch. Make sure it is in the on position. If you have done all of the above and the engine will not fire, then check to see if the fuel is getting to the carburetor. Temporarily disconnect the fuel hose from the carburetor and see if gas pours out. If so reconnect the hose. If not, then check the fuel line. It may be gummed up or the fuel filter is clogged.

Check the Air Filter

Make sure the Air Filter is clean. If it is dirty and oily then replace it. If it just dirty shake it and knock out some of the dust. This may solve your problem; however I would still recommend replacing it.

Clean the Carburetor

First turn off the fuel line. Disassembling and cleaning the carburetor is not as bad as you may think. Usually there is a nut on the underside of the carburetor. Remove this and pull the bottom portion of the carburetor off. Clean the inside of this lower portion of the carburetor and then make sure the float valve moves up and down freely. The float valve is a plastic object about 1.5” in diameter that hangs down when you remove the lower portion of the carburetor.

Reconnect the lower portion of the carburetor and turn on the fuel line again.

Try restarting the lawnmower. If it still does not work after performing all of these procedures, then take it to a repair shop. However, from personal experience these procedures usually solve the problem.

Sharpen the Blade

Finally, make sure you sharpen the blade. This will ensure you minimize the torque on the engine while cutting the grass. Not to mention, your lawn will get a more even cut.