Simple Lawnmower Maintenance
Do you have trouble starting your lawnmower up in the spring? Before deciding to take your lawnmower in for repair, try these few simple suggestions. After completing them, most of the time your lawnmower will fire up and run like a champ.
Most of the time simply cleaning the lawnmower's 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 out why your lawnmower won't start.

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.
Make sure there is oil in the lawnmower and that it is at the proper level.
Make sure there is petrol in the lawn mower. If you have old petrol in the lawnmower and did not put in a fuel stabiliser at the end of the season, replace the fuel. If you had drained the fuel tank at the end of the previous season, then fill the tank at least half full with new petrol.
Like many of us, at the end of the previous lawn mowing season you probably 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 petrol 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.
Make sure the lawn mower 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.
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 inches 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.
Finally, make sure you sharpen the blade. This will ensure you minimise the torque on the engine while cutting the grass. Properly sharpened lawnmower blades gives your lawn a clean and even cut.