Most common problems experienced with small engines are related to fuel. Problems such as difficulty with starting or an engine that doesn't run at a consistent speed is nearly always related to a fuel problem; usually dirty contaminated or stale fuel. It's very important that you keep your fuel clean in storage and to keep it in a container that is not metal and painted where the paint will flake or the rust even may get in and contaminate the fuel- this causes blockages in the mower's fuel system.
Recently forecourt fuel switched to E10 and since then there have been no end of problems with lawn mower engines. The ethanol content in E10 fuel can cause serious damage to your engine components so we advise you NOT to use this. You can user super unleaded fuel from forecourts (E5) which contains 5% ethanol (keep an eye on this) or we recommend a fuel called Aspen. Aspen contains no ethanol, will stay fresh for up to 5 years, emits 99% less toxic emissions and ultimately prolongs machinery life. It's quite expensive but when you're using just a little in a lawn mower then that doesn't really matter so much compared with starting problems and potential engine issues in the future.
Aspen 4 is virtually free from harmful substances such as benzene, aromatic hydrocarbons or olefins; substances that can cause serious health problems to the operator. Aspen Petrol also keeps the spark plugs and combustion chamber of your machine cleaner. Aspen can be stored for a long time without any deterioration in quality which makes your engine easy to start – even after long standstill periods. There are numerous environmental benefits and Aspen fuel is a renewable and sustainable fuel source that produces lower emissions than traditional petrol. This makes it a more environmentally friendly choice for lawn mowers and other small engines.
Find aspen here. You can buy this from your local dealer too or other online retailers
Fuel Stabilisers
We also recommend the use of fuel stabilisers. There are several different fuel stabilisers on the market this keeps the fuel fresher for longer.
Fuel Fit not only keeps the carburettor clean for easy starting but also protects against the corrosive effects of ethanol and maintains fuel stability for up to 3 years.
Petrol actually goes stale after about 30 days of purchase and the fuel stabilisers will help give less starting and running problems.
How to keep fuel as fresh as possible
1. Keep you fuel fresh and store it in sealed containers in a cool dark and dry place (under the bench on a stone floor, rather than on the bench in front of the shed window). Store your machines in a similar manner.
2.Purchase only enough fuel for 30 days use and never ever use fuel over 60 days. You may get away with it but the chances are that you will have problems.
3.Use a fuel additive such as Briggs and Stratton Fuel Fit- your fuel should stay usable for up to 90 days.
4. Always drain your machine before storage in the winter.
5. Use Aspen fuel or E5 super unleaded fuel.
Really old petrol will have a very heavy and unpleasant smell and can be very dark in colour whilst being very thick.