The knocking sound in a stand-on lawnmower refers to the hollow-like, unusual sound it produces when a lot of pressure is exerted on its flywheel. In this state, your mower may be able to move but won’t engage the blades properly.
This unpleasant sound can be a result of an incomplete combustion process in the engine which makes it unable to power the blades and the hydro pumps. Engaging blades will cause an abnormal vibration in the entire mower.
What Causes the Knocking Sound
Worn Out or Wrong Spark Plugs
When your mower has wrong or worn out spark plugs, the electrical spark they deliver in the engine’s combustion chamber will not be enough to ignite or burn the air-fuel mixture that makes your engine operate.
Igniting your mower in this state will cause an unusual knocking sound and since the power the engine is producing is not enough to run the blades, engaging blades will cause a strange vibration in the entire mower.
Using gasoline of an octane rating that is different from what your mower uses can cause an imbalance in the air-fuel mixture resulting into a premature combustion which leads to a knocking sound in your mower’s engine.
When Air Filters Are Damaged or Clogged with Dirt
Air filters serve the purpose of filtering the air that goes in the combustion chamber of your mower’s engine. The air filters on your mower’s engine air to ensure that the combustion chamber doesn’t ingest dirt, pollen, or grass clumps.
If your air filters are damaged or clogged with dirt, the engine will receive contaminated air making it produce an unusual knocking sound.
General Mechanical Problem
Wright Stander lawn mowers use Kawasaki engines which are made with a low-tone muffler to help reduce the noise they produce. So if your engine produces an abnormal sound then, there might be a mechanical problem.
What You Can Do
Here are some things you can do yourself that might help you save the money you would spend hiring a mechanic:
- Clean or replace the air filters ( Most Standers use Kawasaki engine air filters.)
- Clean and re-gap the spark plugs ( This might require a Spark Plug Cleaner and a Spark Plug Gap Tool.)
- Consider replacing spark plugs in case they are worn out ( Most Standers use NGK spark plugs.)
- Try gasoline of a different octane rating.
Once you have cleaned or replaced the air filters; Re gaped or replaced the spark plugs; Refilled your Stander with a different fuel, Ignite it and see if the knocking sound disappears.
If the problem persists, then, it might be a general mechanical problem which might require getting a mechanic to perform further checks.
Those are the tips, try them out and see if the unpleasant knocking sound in the engine of your Stander disappears. If you have any question, feedback, or a helpful tip, feel free to leave your comment below.