Lawnmower Tune Up

Clean or Replace Lawnmower Spark Plug

A dirty spark plug or improperly gapped spark plug can cause your lawnmower engine to run rough or not all. Pull the spark plug and clean it with some WD-40. Also re-gap it per your lawnmower’s specification.

Inspect Lawnmower Fuel Line

Another often forgot about lawnmower tune up item is to inspect the fuel line for cracks and clogs. Also, if there is a fuel shut off valve, make sure you turn it to the ON position so that fuel can flow into the lawnmower’s carburetor.

Clean Lawnmower Air Filter One of the big culprits in a poorly running lawnmower is a dirty air filter. Lawnmower air filters are notorious for getting dirty due to all of the dust and grass clippings they kick up. Remove the lawnmower air filter and shake it to remove the dust. Then rinse it with clean water and let it dry out. You may also want to consider replacing the lawnmower air filter as they are very inexpensive. Sharpen the Lawnmower Blades Dull lawnmower blades do a poor job cutting the lawn and stress the engine. With the spark plug wire disconnected remove the lawnmower blade(s) and sharpen them with a file.

Tighten Wheel and Handle Nuts and Bolts

Lawnmower wheel and handle nuts and bolts frequently loosen up over a lawn mowing season. Be sure to make sure they are tight before firing up the lawnmower this season.

Clean the Lawnmower Carburetor

If after performing the other mentioned lawnmower tune up steps the engine still runs rough, clean the lawnmower’s carburetor

To clean the carburetor first turn off the fuel line and empty any fuel from the tank. Next, star the process of disassembling the carburetor by removing the nut on the underside of the carburetor assembly. After removing the nut, pull the bottom portion of the carburetor off. Use a small rag and WD-40 to clean the inside of this lower portion of the carburetor. Also inspect the float valve and make sure it moves up and down freely. The float valve is a plastic or hollow metal object about 1.5” in diameter that hangs down when you remove the lower portion of the carburetor.

Refasten the lower portion of the carburetor with the nut, add some gas to the lawnmower and turn on the fuel line. Finally reconnect the spark plug wire to the spark plug.

Try starting the lawnmower. If it starts up smoothly and runs fine your lawnmower tune up is complete. If it does not start up and run smoothly then unfortunately you may have no choice but to take it to a repair shop recommend by the lawnmower manufacturer.