How to service a petrol lawn mower

How to Service a Petrol Lawn Mower

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A petrol lawn mower offers unrivalled cutting power and many other benefits, yet one drawback is the need for regular maintenance. Just like a car engine, a petrol lawn mower engine requires servicing, otherwise you could encounter some issues down the line that would have been avoidable.

While maintenance seems like a chore, you can’t overlook its importance, as maintaining it ensures optimal performance and durability over the long-term. In fact, if you take the time to regularly clean and maintain the mower, expect it to last for many years, if not decades!

Here’s a breakdown for to properly service a petrol machine:

Always Read the Manufacturer Manual

We are all guilty of buying things and never reading the instructions or user manual, but this is incredibly important when servicing your mower. Each component of the engine and mower requires a unique approach, so by reading the manual, you will know exactly what is required when completing maintenance.

Disconnect Spark Plugs

The spark plugs ignite the fuel in the mower engine, with the engine powering the cutting blade, so it’s an important component in the mower. Before you start on any maintenance, always disconnect the spark plugs to ensure there is no chance of the engine kicking into life and moving the blade as you work.

Given that you’re going to be working on the blades, you want to make sure it’s completely safe to work on, which is why you need to remove the spark plugs. If left connected, the plugs could inadvertently start the mower as you work on it, which is obviously incredibly dangerous and the last thing you want.

Leave them disconnected until all other maintenance is complete – you may even want to replace them if the mower is a bit older.

Drain Petrol at the End of the Season

This one is easy to overlook but don’t make the mistake of leaving fuel inside of the engine over winter! In fact, you should never leave fuel in the engine for more than 30 days, so make sure to drain the engine entirely after the final cut of the season, usually in late autumn.

Leaving petrol for longer than 30 days can result in a significant drop in quality, which in turn lowers fuel performance and could possibly damage the engine. So, make sure there is no engine fuel left inside the mower when storing it over winter.

Remove Debris from Underside and Air Inlets

Old clippings can quickly accumulate over the mower, mainly on the underside and around the air inlets. Once you know it’s safe to work under, give it a thorough clean to remove all loose debris, also removing any from air inlets, as this may lead to clogging and engine troubles down the line.

Bear in mind that some petrol models cannot be moved onto their side, as it may cause fuel and oil to leak from the engine, so make sure that you have read the manufacturer guide to ensure it’s safe to tip.  

This type of maintenance can be done after each cut. In fact, it is generally easier to do straight after mowing as the grass clippings are still moist so can be removed with less effort. Regardless, be careful around the blade when clearing debris!

Check for Loose Bolts

Your engine probably won’t have any loose bolts but it’s good not to leave it to chance, so give it look over to see if there are any bolts or screws loosening up. If so, simply secure them back in place and you are good to go.

Check Wheels

Like above, check the wheels to see if any are loose and need tightened. A season worth of mowing can loosen the wheels up, making the machine difficult to manoeuvre, so it’s always worth checking to make sure the wheels are secure. If you tighten a loose wheel and find it’s still wobbling then it may be a problem with the wheel itself.

Replace Air Filters

Because the air filter protects the engine from dust and debris, it’s a vital component that needs to be properly cared for. In most cases, it is recommended that you change the filter every three months for optimal performance, while you should clean the filter housing any time you are replacing it.

Change Oil

Just like a car engine, your mower engine needs regular oil changes to keep everything lubricated and in top condition. How this is done varies from each machine, so check the user manual and follow the instructions carefully – it should be easy enough to complete.

Make sure you dispose of the old oil properly – you could be breaking the law if you don’t.

Check out our buying guides on cordless mowers and manual mower models.

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