Below is our sit on lawn mower petrol engine trouble shooting guide for common problems and remedies associated with most modern single cylinder 4-cycle engines. This guide is not exhaustive and your machine’s instruction book may provide alternative solutions to these problems.
The engine will not start on my sit on lawn mower

  • Ensure the fuel tank has enough fuel

  • Inspect fuel tank and fuel delivery pipes for contamination or blockage, replace fuel filter if required

  • If fitted, make sure any fuel cut off valve or switch is in the open position

  • Check for loose electrical cable connectors on the battery and tighten if necessary

  • Check for loose cable connectors on the machine’s safety switches

  • Remove and inspect spark plug for wear or damage and replace if necessary

The engine on my sit on lawn mower refuses to turn over

  • Battery is flat and will require recharging

  • Main fuse has blown. Replace with new fuse of same amperage

  • Inspect electrical wiring for any damage and repair any damaged wires

  • Check for any loose electrical cable connectors on the sit on lawn mower

It is difficult to start the engine on my machine

  • Ensure there is sufficient oil in the engine

  • Inspect the air filter. Clean or replace the filter if necessary

  • Remove and inspect spark plug for wear or damage and replace if necessary

  • Check the fuel filter for blockage. Replace filter if required

My sit on lawn mower engine loses power or is not running easily

  • Check engine oil level

  • Examine air filter and housing for grass cuttings etc. Clean as necessary

  • Check for dried matter, like leaves, around engine. Clean engine carefully with a brush

  • Check spark plug for wear or damage. Replace if required

  • Engine under strain. Select lower drive gear

  • Grass too tall. Raise cutting deck

  • Make adjustment to carburettor

  • Inspect fuel filter for contamination. Replace filter if necessary

At fast speeds, my machine’s engine does not run smooth

  • Check spark plug for damage and wear. Replace if necessary

  • Inspect throttle mechanism and cable and make adjustments if required

  • Check air filter and clean as necessary

  • Inspect fuel filter for debris. Replace if required

My sit on lawn mower’s engine does not idle

  • Inspect throttle control and cable and adjust if required

  • Check spark plug for wear and damage. Replace if necessary

  • Ensure air filter is clean

  • Make adjustments to the carburettor