This article will cover the soft fixes you can perform if your lawnmower is hunting.


TABLE OF CONTENTS


What is Engine 'Hunting'?:

This is when the engine revs up and drops back down rapidly on a cycle. It is usually caused by a lean fuel mixture - ie.) not enough fuel in the fuel-air ratio. This is controlled by your carburettor and governor.


What can I do?

Firstly, please ensure that your grass is not too long or too wet as this can overwork the engine.


1. Checking the fuel

  • Please make sure that you are using unleaded fuel that is no older than 30 days.
  • If the fuel you are using is older than 30 days, please remove and replace the old fuel.


Replacing the fuel in your lawnmower

  1. First, please remove the air filter from the lawnmower.
  2. To remove the air filter, unclip the filter cover on the side of your engine.
  3. Some models may use a securing screw which can be removed by hand or using a screwdriver.
  4. You may then remove the existing fuel by unscrewing the fuel cap, tipping the lawnmower onto its side and emptying the fuel into a container.
  5. Once you have removed the existing fuel, refit the air filter and clip the air filter cover back on.
  6. Then, place some fresh unleaded fuel into the tank.


2. Check the air filter

  • Please identify whether you have a sponge or paper air filter.
  • To access the air filter, please unclip the filter cover on the side of the engine.
  • Some models may use a securing screw which can be removed by hand or using a screwdriver.


Sponge Air Filter

  1. A clean sponge air filter would be either grey or yellow.
  2. If you have a sponge air filter which is dirty, you may clean the air filter using warm soapy water.
  3. Please ensure you leave the filter to fully air dry before reinstalling.

Paper Air Filter

  1. A clean cartridge air filter would be white in colour.
  2. If you have a paper air filter, it is not possible to clean the air filter.
  3. If the air filter is dirty or damaged then you will need to purchase another filter.

3. Removing and checking the Spark Plug

Tools-

Spark plug tool


  1. Please ensure that the spark plug is not dirty.
  2. If your spark plug is dirty, please clean the spark plug by following the instructions below.
  3. You will need the spark plug tool usually provided with your lawnmower.
  4. Firstly, removing the spark plug cap.
  5. Then loosen the spark plug using the tool in an anti clockwise direction, until it comes out of the engine.
  6. Once the spark plug has been removed from the engine, clean the end of the spark plug with a wire brush.
  7. Once the spark plug has been cleaned you may refit the spark plug into the engine.
  8. Screw the plug in by hand to prevent cross threading, then use the tool to tighten.
  9. Refit the cover ensuring it clicks into place.


**If it is still hunting - Carb Jets:**

  • It is most likely that the jets are blocked inside your carburettor (the part which regulates the fuel into the combustion chamber).
  • You can either try cleaning it yourself (purchase a 'carburettor cleaning kit'), or taking it to a local garden machinery centre for a service.