A lawnmower that is full of old or bad gasoline is unlikely to perform properly. If gasoline is left in the lawnmower for too long, it can start to turn into a gooey varnish that will clog engine parts. To prevent gas from turning into varnish or otherwise going bad, it may be a good idea to use a fuel additive.
How Long Does Gasoline Last?
Generally speaking, gasoline will last for about 90 days after it leaves a gas station pump. Therefore, you generally don't have to worry about gas going bad during the spring and summer months when you'll likely be mowing your lawn every week or two. Even if you do have fuel that is a few weeks old currently sitting in your lawnmower, it may be possible to rejuvenate it by mixing it with newer fuel.
Fuel Additives May Be Ideal When Winterizing Your Mower
There is a chance that you'll have some gas left in your mower's tank after you cut the grass for the final time in the fall. If you don't want to drain the tank before putting your lawn mower away for the winter, it may be worthwhile to add a fuel additive. Generally speaking, such a product may prevent gas from going bad for up to a year. This means that the fuel should still be good to use regardless of how long the winter season is in your area.
The Key Reason for Keeping the Fuel Tank Full
Draining the gas tank before when you won't be using it for long periods of time may seem like the easiest way to prevent damage to a lawnmower's engine. However, there is no guarantee that there won't be a small amount of fuel left in the tank even after it has been drained. Over time, condensation can collect in the tank and mix with the gas, which can cause it to go bad or otherwise harm your machine. By keeping the fuel tank filled at least halfway, you can prevent condensation from occurring.
The Potential Drawbacks of Using Fuel Additives
While fuel additives can help preserve the gas in your lawnmower, they cannot prevent gas that is already bad from harming its engine. Furthermore, as fuel additives are made from many of the same substances that are in unleaded or diesel gasoline, they can cause environmental issues if not stored properly. Finally, if your mower's gas tank isn't sufficiently full, a fuel stabilizer will do little or nothing to prevent condensation from occurring.
Following a regular lawn mower maintenance schedule helps to ensure that it will last for most or all of its useful life. In addition, a mower that is regularly maintained may cost less to own throughout that period. Ideally, you should consult the owner manual or contact the company that made your machine before adding anything to the gas tank or engine.