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Petrol Lawn Mowers: Getting the engine started

The lawn mower is an essential tool for the garden. As the sunnier months approach, we will find lawn mowing to become a weekly/monthly chore again. For petrol lawn mowers, you may be used to re-attempting to start if you have not pulled the cord hard enough. However, if you are pulling correctly but the engine isn’t starting, there might be something else preventing it. In this article we have highlighted the essential checks to carry out to get your engine started. 

Is the throttle in the right position?

Your lawn mower will have a throttle lever, usually located on the side. For most lawn mowers it will need to be in a mid-high position to operate and continue running after the cord has been pulled. Without this, it means that once you let go of the cord and start mowing it will cut out. This can be easily resolved by moving to the correct position to keep the engine running. 

Does the engine need priming?

Depending on your lawn mower, you may find that the engine needs priming. Lawn mowers have a primer, which helps to fill the carburetor with fuel. If this is not working correctly, you may need to manually push the primer bulb. This instruction will vary by model, but generally you will need to push the primer bulb 3-5 times to deliver the correct amount of fuel to the carburetor. This is an easy way to get the fuel flowing and engine running. 

Has the engine flooded?

It is possible for the engine to flood which will prevent the engine from operating. An indicator of this is if you notice the spark plug to be wet or if you notice a strong smell of fuel. To rectify this, simply leave to settle for 20-25 minutes to allow the unit to dry out completely. Once dried, try the lawn mower again. 

Has the tank ran low?  

A low fuel tank can also cause problems. Without a sufficient fuel supply, the engine will be unable to operate. This can be easily rectified by filling the tank up to the ‘MAX’ level and trying to start it again. 

When was the lawn mower last used?

You may need to consider when you last used your lawn mower in case there is an issue with the fuel. Over time, fuel can become stale if left in the tank and thus become ineffective for your mower. To resolve this, we recommend emptying the tank of old fuel and refilling with new fuel. 

Is the spark plug cap fitted correctly?

Spark plugs are important to help with the engine starting on your lawn mower. They work by creating small sparks to help the ignition. Without this, the engine will not start. This may not operate if it is not fitted correctly. You should try removing it and refitting, correctly aligning with the unit. Whilst it should be tighten, ensure not to over tighten to avoid damaging the plug. 

Is the spark plug dirty?

Similar to keeping the spark plug cap fitted correctly, it is important to keep it clean. If it becomes dirty, debris may cover the contacts making it difficult for the plug to ignite. You can fix this by removing the spark plug and using a small, clean brush to wipe away the debris. Never use any harsh abrasives or cleaning tools. 

Does the spark plug need replacing?

You may find that the spark plug needs replacing entirely. This might be due to the age of the product, or that it has just become worn over time. To replace it, simply remove the old spark plug and replace with a new. This should help to ignite and get the engine running. Always refer to your user guide information for the required specifications of the spark plug. 


To summarise...

You can solve most engine starting issues by carrying out these soft checks. If you are ever in doubt or require further assistance, always contact the relevant support team or refer to your user manual. 

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