This issue is often encountered if either of the following occurs:
- A mower is stored over winter without emptying it of fuel first
- If old fuel is used to top up the lawn mower
It is important to use ‘fresh’ fuel in any engine and avoid using fuel which is older than 30 days old. This is because modern fuel contains ethanol which absorbs water from the air and contaminates the fuel causing it to separate (as shown in the picture below).
It can also cause corrosion and blockages in the fuelling system, resulting in poor engine performance. If left unchecked, it can damage your engine.
Symptoms of contaminated fuel may include the following:
- Mower will not start
- Rough running
- Engine revs hunting (increasing and decreasing)
- Cutting out
Universal Fuel Stabiliser is a fuel additive that will keep fuel fresh for easy starting and maximum performance for up to 2 years. If you are likely to keep fuel stored for longer than 30 days, adding this product to your fuel when you purchase it will help to avoid fuel contamination.
This issue is easily resolved by simply draining the mower of fuel entirely via the carburettors float bowl as described overleaf and refilling with fresh fuel.
Honda engines
What you will need –
- 10mm spanner
- Container to catch the fuel
- A cloth or rag
Locate the float bowl drain bolt on the carburettor. This is the single bolt underneath the carburettor as shown in the photo fig 1.
Place a cloth or container underneath the drain bolt to catch the fuel that is drained from the carburettor.
Using a 10mm spanner, loosen the drain bolt and allow the fuel to drain out of the carburettor into the container as shown in fig 2.
Tighten the drain bolt and refill with fresh fuel.
Wipe away any spilt fuel and start as normal.
Mountfield engines
What you will need –
- 10mm spanner
- Container to catch the fuel
- A cloth or rag
Locate the float bowl drain bolt on the carburettor. This is the bolt underneath the carburettor at an angle on the float bowl as shown in the photo fig 3.
Place a cloth or container underneath the drain bolt to catch the fuel that is drained from the carburettor.
Using a 10mm spanner, loosen the drain bolt and allow the fuel to drain out of the carburettor into the container as shown in fig 4.
Tighten the drain bolt and refill with fresh fuel.
Wipe away any spilt fuel and start as normal
