Tired of yanking on that starter cord until your arm hurts? If your machine is not starting up as soon as it should, perhaps it’s time for a lawn mower tune-up (tuneup, tune up). Although it’s often possible to get by without one, it is recommended that you have a lawn mower tune-up each year. The instructions below show you how to tune up your machine yourself.
Before performing a lawn mower tune-up, you need to warm up the engine. Put just enough gas in the gas tank to get your lawn mower running. Start your engine and let it run until it runs out of gas. Finally, now that you’re ready to perform the lawn mower tune-up, you need to take a safety precaution: disconnect the spark plug wire so that the engine can’t start accidentally.
A lawn mower tune-up essentially consists of three tasks (although maintaining your machine entails much more than this), each of which I’ll describe in more detail below:
- Changing the Oil
- Changing the Spark Plug
- Changing / Cleaning the Air Filter
Lawn Mower Tune-Up Task 1: Steps for Changing the Oil
- Make sure you purchase the right type of oil for your replacement oil. When in doubt, ask where you bought the machine. Or, if you’re really desperate, check the owner’s manual….
- Clean off any dirt around the upper part of the oil tank (where you fill your machine with oil). An old toothbrush comes in handy for this task. Unscrew and remove the dipstick, if your oil tank has one.
- Now locate the lower side of your oil tank – a plug found on the underside of your machine. You need to drain out the old oil, and unscrewing this plug will do just that. Prop up your machine accordingly with blocks, providing a tilt that will give you access to the plug. Stick an oil pan or like container under the plug to catch the oil. Ready? Okay, unscrew the plug (you may need a socket wrench) by turning counter-clockwise and let that dirty oil pour out. And I do mean dirty: obviously, you don’t want to have your “Sunday best” on when performing a lawn mower tune-up!
- Screw the drain plug back on using a clockwise motion. Don’t over-tighten, so that you’ll be able to get it off easily next time you need a lawn mower tune-up. Rather than over-tightening when you work on your machine, it’s better to tighten moderately, then periodically check during the mowing season to ensure that it hasn’t loosened through vibrations.
- (For machines that have an oil filter) If your machine has an oil filter, replace it as part of the lawn mower tune-up and clean the gasket with which it comes into contact.
- Remove the blocks so that your machine is level again.
- Fill the oil tank with new oil to the correct level, replacing cap and dipstick.
- Refill lawn mower with gas and reconnect spark plug wire.
- At this point in the lawn mower tune-up, it's time to start the machine. Let the engine idle and ensure that there are no oil leaks.
Lawn Mower Tune-Up Task 2: Steps for Changing the Spark Plug
- Disconnect spark plug wire.
- Clean the housing around the old spark plug.
- Remove the old spark plug with socket wrench.
- Unfortunately, at this point you’ll have to check the blasted manual again (don’t you just hate that?) What you need to do is ensure that the new spark plug is gapped the way it’s supposed to be for your machine. Just measure the gap, then see if the measurement matches manufacturer's specifications for your machine. If it doesn’t match (or if there’s no gap at all), you’ll have to create/alter the gap.
- Screw on the new spark plug (not too tight!).
Before changing/cleaning the air filter, first determine whether your machine has a paper or foam air filter. Paper air filters are replaced; while the foam ones are cleaned.
Lawn Mower Tune-Up Task 3A: Steps for Changing a Paper Air Filter
- Unscrew the cover and remove the paper air filter.
- Insert a new paper air filter with the pleat facing out.
- Screw the cover back on.
Lawn Mower Tune-Up Task 3B: Steps for Cleaning a Foam Air Filter
- Unscrew the cover.
- Remove air filter unit and discard the old foam.
- Clean the air filter unit with kerosene.
- Soak the new piece of foam in clean engine oil. Squeeze out the excess oil using a clean rag.
- Insert new foam in air filter. Ensure the lip protrudes over edge of the unit.
- Screw the cover back on.
- Re-connect spark plug wire.