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Servicing & Mechanical

Service Your Lawnmower

It’s that time of year where the lawn seems to grow faster than you can cut it. Is your mower up to the task?

So your neighbour has been ripping the pull start for 15 minutes, just got the mower going and it stalls on the first blade of grass.

While he walks inside cursing the machine, you can trim the whole lawn down without skipping a beat!

By the end of this article you’ll have all the knowhow to service your mower and make lawnmowing a breeze.

First, some general cautions

  • Safety gear. Wear appropriate PPE. Safety glasses and gloves at a minimum
  • Tipping a 4 stroke mower. These have an oil filled sump. If it is turned upside down or tilted with the cylinder head down; oil can make its way into the combustion chamber. Always tilt it so that the cylinder head is facing up
  • Take steps to isolate the engine. Disconnect the spark plug, cut off the fuel, switch off the ignition
Servicing a Mower

Step 1: Begin with a clean

Why should I clean my lawnmower? There’s a few reasons. Firstly, it’s hard to work on when it’s covered in grass. Second, damp grass clippings trapped around the engine and chassis can cause rust. A quick brush down will do the trick, both on top around the engine and underneath.

Step 2: Check the fasteners

Go over the chassis, handle, wheels of the mower and give it a good jiggle to check for loose nuts and bolts. Everything on the engine should be okay, but watch the throttle and choke linkages on the carburettor as you move them for anything that doesn’t look right.

Step 3: Lubricate moving parts

Grab a can of WD spray or similar lubricant and go over linkages on the carburettor, throttle cable, height adjuster and wheels.

Step 4: Check the air filter

How do I know if my mower needs a new air filter? An old air filter can cause trouble starting, and running rich. Remove the air filter and tap or blow it out. If it remains quite filthy, replacing a lawnmower air filter is a cheap and easy job.

Oil check a mower

Step 5: Check the spark plug

Pop the spark plug out and clean it up with a wire brush. You can easily find a spark plug wear chart online and compare your plug against this to determine if there’s any life left in it. Two stroke mowers are known to need more frequent spark plug replacement and doing so will often see a massive improvement in starting and running.

Step 6: Check and/or replace the engine oil

This one applies to four stroke mowers only. Pop the dipstick out and check for both the correct oil level, and nice golden colour. If it’s looking dark brown or black, it’s time to replace it. You’ll find a drain plug on the engine, and new oil is generally filled through the dipstick hole. A lawnmower typically needs between 500ml and 1 litre of oil.

Step 7: Inspect the blade

Is it nice and tight? Run a spanner over it if needed. Are they nice and sharp? Blunt blades will damage your lawn, keep them sharp and keep the lawn healthy. Look out for stone damage and either replace the blades or have them professionally sharpened.

And finally, a note on fuel

Unleaded petrol can go stale in as little as 30 days in poor conditions! This is the number one cause of starting difficulties and rough running. Further to that, fuel left in the tank can varnish the fuel lines and carburettor which leads to all kinds of trouble! It’s good practise to run the mower dry of fuel when you’re done, and use a fuel stabiliser in your gardening fuel can.

Owning the best looking lawn in the street is SO much easier with a smooth running lawnmower! Return to this checklist every month or two and you’ll love your mower every time you pull the starter cord.