What regular maintenance should I do on my lawn mower?

Proper mowing is important, and winter is a good time to perform some simple maintenance and winterizing on your mower to ensure good performance in the coming year. Many lawn mowers have been around for a long time.

Maintaining and caring for them has become a major service industry. A typical tune-up of a 2 or 4 cycle lawn mower can run anywhere from $30 to $50 and higher. A basic tune-up of a lawn mower that was running good last year is not very difficult. If your mower has been difficult to start or runs ‘rough’, we suggest you take it to a professional small-engine mechanic. If your mower was running okay at the end of last year, a simple tune-up should keep it running well this year.

The first thing to do is to change the oil. Before doing this, though, determine whether you have a 2 or 4 cycle engine. If you have to add oil to the gasoline that you use for your mower, then it is a 2-cycle engine. This type of engine uses oil that is mixed with the gasoline to lubricate the pistons and crankshaft. If you have this type of engine, you do not need to change the oil. If you do not add oil to the gasoline, then you have a 4-cycle engine and the oil does need changing at least once a year. Small 4-cycle engines normally use non-detergent oil.

Check the manufacturer’s recommendations in your owner’s manual for the correct viscosity, grade, and amount of oil to use in your mower. Before performing any repair or maintenance work on your mower, always disconnect the spark plug wire. This will prevent any accidental start-ups of the mower.

The oil drain plug is located at the bottom of the engine, but not in the same location for every model of small engine. Again, consult your owner’s manual for the location of the drain plug. This can be a messy job, so be sure you have a drain pan to collect the old oil. Once the drain plug is removed, the oil will pour out quickly. Dispose of the used oil at an oil recycling center and not in the trash or down the drain. Once the majority of the old oil has drained out, replace the drain plug and add the correct amount of new oil as recommended by the manufacturer.

Oil Changing Hint:

Open up a step ladder, and lay it level, on its side. Set the mower on top of the spread ladder legs and you have a “Mini-Grease Rack” for the mower. This gives easy access to the oil drain plug.

Spark plugs should be set at the proper gap for best performance.

The second task is to replace the spark plug. You may need to purchase a special spark plug wrench if you do not have access to a deep-well socket. Spark plug wrenches are available at any hardware store and are inexpensive — less than $5. The old spark plug has a number engraved on it that will identify it. Get the same type or recommended replacement. Spark plugs should be set at the proper gap for best performance. The end that fits into the engine has a tiny metal rod that extends from the plug. There is another piece of metal that is L-shape that extends over the tiny rod. The ‘gap’ refers to the distance between the tiny metal rod and the L-shape metal piece. Within that space, a spark is generated that ignites the gasoline that makes the engine run. A common spark plug gap is .045mm, but some are different. As you may have guessed, your owner’s manual will give you the correct spark plug gap. An “old timer’s” trick was to gap the plug using the cover from a paper matchbook. If the cover slides easily in the gap area, then it’s fairly close to .045mm. The accurate way to check is to use a gapping tool. Your hardware store or local mechanic should be able to check it for you.

Before you take off the blade, make a mental note of how the blade is placed on the shaft.

It is a good idea to drain the old gasoline out of the tank. If you cannot complete this easily, then add a few drops of a commercially available gasoline stabilizer.

It is always a good idea to clean out under the mower deck. Take care when tilting the mower so the oil or gasoline does not leak out. Wet grass clippings often get ‘caked-up’ under the deck and reduce the mower’s suction ability. Take a putty knife to scrape the underside of the deck. Next, remove the mower blade. Be very careful, as the blade is (hopefully) sharp and can cause serious injury.

Before you take off the blade, make a mental note of how the blade is placed on the shaft. More than one homeowner has replaced the mower blade upside down. Mowing will be extremely difficult if you do this and your lawn will look horrible. Generally, the fins on the blade face up into the deck and the flat side goes down.

Sharpening the blade is best done by a professional service. There is a specific angle that needs to be maintained, or the blade will dull quickly. Many hardware stores and mower repair services will sharpen your blade for $5 to $10. It is worth the expense to sharpen the blade correctly. Some mower manufacturers recommend blade replacement over re-sharpening the existing blade. Check your owner’s manual for their recommendations.

A good lawn mower costs $300 or more, so take a little time to perform some preventive maintenance.

Make a general inspection of all the nuts, bolts, and screws on your mower. Tighten any that are loose. Position all the wheels at the same height. Set the mowing height at the level that is best for the grasses in your lawn.