Changing Your Lawn Mower Engine

During the spring and summer months, mowing the lawn becomes something of a weekly routine. Due to heavy use, the engine of your mower may suffer from the effects of wear and tear; however, rather than replacing the whole mower, it may be more economical to change the engine. All lawn mowers follow the same basic principal – a rotated blade is powered by a motor.

There are two types of lawn mower – the rotary mower and the self-propelled mower.

Rotary Mower

This is the most common garden mower, powered by an internal combustion engine that runs on either two or four stroke cycles. The two-stroke cycle burns a mixture of fuel and oil, whereas the four-stroke cycle burns fuel with a separate lubrication system. Handle bars are attached to the body of the mower and an operator stands behind, pushing the mower forward. The blade is located within a casing called the deck – the deck prevents the grass from becoming too widely dispersed when cut by the blade, a bag is attached to collect the grass cuttings. The rotary mower is also available with an electrically powered motor, which runs using either a cord or a rechargeable battery.

Self-Propelled Mower

Generally the preferred mower for larger gardens, parks and other large lawned areas. This mower has a transmission that turns the wheels using the power of the motor, typically the operator sits in an open cabin on top and steers the mower.

Replacing Your Engine

Key Considerations

The engine must be compatible – check the size and type and that they are exactly the same (ideally the same brand). Locate the brand's original engine model type number to make sure the replacement is correct.

The starter type, position, fuel tank location, fuel line routing, exhaust direction of the original engine should all be maintained.

Verify horse power measurement (the frame of the lawn mower needs to withstand the power of the engine).

Check the crankshaft orientation and size to ensure it is of the correct fit.

Replacement

Always wear safety gear, overalls, gloves and safety glasses

• Unscrew the lawnmower blade – this will be screwed on tightly and make take some time
• Safely drain the fuel and oil by tipping the mower onto its side
• Disconnect any electrical wiring and the throttle cable
• Remove all the bolts connecting the deck to the engine and then carefully remove the engine
• The new engine will fit into the same position – following the same steps in reverse, firmly bolt the new engine to the deck, connect all the wiring and screw on the lawnmower blade
• Refuel your new engine with either petrol or diesel depending on the model.
• Fill oil with the appropriate lawnmower lubrication

Call AT Wilde and Son Ltd today for expert advice on replacing your lawn mower’s engine.