Lawn Mower Maintenance Tips

It’s pretty likely that you’ll fork out a fair bit on your lawn mower, especially if you’ve got a large lawn and require a more powerful machine. All too often however many people neglect their mower, thrashing it into submission until it breaks or conks out for good. This equals a short change on your initial investment which could easily be avoided by a few simple maintenance tasks and checks. Number one on this list of tasks is (unsurprisingly) to read the manual, but you’d be surprised at how many people don’t even think to do this! It contains manufacturer specific instructions that will ensure that your mower performs exactly as intended.

Other than reading the manual there are a few other key points to bear in mind, particularly with petrol driven mowers which have more components and moving parts than their electric counterparts. Some of these checks should be carried out on a ‘mow by mow’ basis, whereas others only need to be done either at the beginning or end of the season, or after so many hours of use. Again your manual will advise best practice on this.

1. Check the Oil.

Ensure that it’s topped up to the correct level (see manual), that there isn’t any debris floating in amongst it, and that it hasn’t turned dark black as this is a sign that it’s past it’s best. Should you need to change the oil, ensure that it is completely drained before replacing, and refer to the manual for the recommended type.

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Above: Checking oil level, ensure that the oil only covers the dipstick in the area indicated, in this case by a textured ‘criss cross’ pattern.

2. Change the Spark Plug.

Essential to getting the mower to start, it’s best to replace the spark plug(s) once a year to keep your mower firing properly. When replacing simply remove the connecting wire and unscrew the plug with a socket wrench, reversing the procedure to fit a new plug. Ensure that you don’t over tighten the plug however, as this could cause problems starting the mower. If you’d prefer to try and get more life out of your existing spark plug, use a feeler gauge to check that the distance between the contacts is as per the manufacturers instruction, and either gently give the end a tap to decrease the distance, or use pliers to carefully prise the contacts apart to increase the distance.

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Above: Removing the spark plug, clockwise right to left: 1) Disconnecting the spark plug cable, 2) using a socket wrench to unscrew the spark plug, 3) The disconnected spark plug, 4) Feeler Gauges, 5) Checking the gap between the contacts, 6) The correct gap between the contacts

3. Drain Unused Petrol at the end of Each Mowing Session.

Old petrol can cause problems with starting so it’s best not to risk it, especially with 2 stroke engines. If you’re mowing regularly in the summer months then you may be able to get away with leaving this task until the end of the season, just don’t forget! If it’s easier, run the engine dry rather than manually emptying it.

4. Inspect/Replace the Air Filter.

A clogged filter can reduce the engine performance, and result in more petrol being burned than necessary. Replace annually for optimum performance. For mid season cleaning, remove the filter and tap the casing on a hard surface to dislodge any excess dirt, or if you have access to it, use a compressed air line to blow the dirt clear. Never use a brush to clean the filter as this will force dirt into the filter fibres.

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Above: Checking the air filter, note the blackening of the blue filter fibres as a result of dirt ingress.

5. Clean Underneath the Deck.

When grass collects on the underside of the mower it can block the grass collection chute, keep it clean with a wire brush and hose, but ensure you disconnect the spark plug first for safety reasons.

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Above: Cleaning the underside of the deck and the back of the mower. Use a stick to scrape all the grass clear especially around the motor drive shaft and in the path of the grass as it enters the collection box.

6. Sharpen the Blade.

As the business end of the mower the blade is subject to an awful lot of punishment, from stones to lumber, and this can wear the blade down over time, eventually resulting in it tearing rather than cleanly cutting the grass. If you have the tools and ability you can sharpen the blade yourself. Ensure that the spark plug is disconnected and use the appropriate wrench to unscrew and remove the blade, then clean it with wire wool before using a file to sharpen it.  It can be quite a laborious task however, so seek assistance from a mower repair shop if you prefer.

7. Get a Professional Service.

A mower maintenance shop can carry out all the above checks and maintenance to a high standard, and will be able to help diagnose any other issues that you may be having with your mower, for example if the blade or drive shaft are bent.

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