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Serving the Buffalo Area since 1995

Scherer Electric Blog

Old Fuel and Your Generator: A Bad Combination


We strongly recommend whole-house generators to our customers. There are few things more reassuring than knowing that your home will have the electrical power it needs in case of an extended outage.

Power losses are most common during periods of extreme weather, and a home that cannot run its HVAC system for several days at a time under such conditions is likely to be unlivable.

Generators also make homes safer in general, stop refrigerated and frozen food from spoiling, and ensure that powered medical equipment continues to operate.

The best way to power a generator is with natural gas, since this fuel source is piped directly to the generator and there’s no need to keep a separate fuel supply of liquid propane, gasoline, or diesel on hand.

But not all homes have access to a natural gas line. For those homes that rely on a different fuel source, we have some important advice about old, stale fuel.

Fuel Quality Worsens Over Time

Fuel doesn’t age like fine wine, nor does it remain at the same quality level over years. Fuel turns stale with time as oxidation sets in and makes the fuel more viscous (i.e. resistant to flowing).

This is similar to the oil used in vehicle engines—and you probably know how damaging old oil can be for a car engine. The fuel will lose its effectiveness over time and may eventually provide no energy at all to a generator.

The problem is often worse than simply the fuel losing its ability to provide energy. It can also harm the generator because of the impurities due to oxidation.

When these impurities are run through the generator’s components, they will start to clog pistons and the carburetor. This will at first affect the generator’s efficiency and eventually cause it to stop working. One major danger is that poor quality fuel will cause the generator to overheat.

The viscosity also places greater strain on components, shortening the generator’s service life. A generator that suffers damage from old fuel will need extensive repairs and in many cases may not be salvageable. 

How Long You Can Keep Fuel

If you have fuel stored away for use in your generator, understand that it still won’t be as “fresh” as fuel taken on delivery. It will suffer some decline in efficiency, although it won’t necessarily be harmful to the generator. Fuel that is more than one to two years old, however, is potentially harmful and you shouldn’t keep it around. 

The Fuel Already in Your Generator

You also need to be aware that the gas supply already in your generator can go stale. It’s at the same risk of a decline.

This is one of the reasons we recommend all our customers arrange for generator maintenance in Depew, NY with our team. Each year, we’ll inspect your generator and give it a tune-up to ensure best performance.

Part of the inspection is to check on the fuel source to see if it needs to be replenished because it has gone stale. 

Scherer Electric Is Western New York’s Favorite Electrician! Arrange for all your generator services with our electricians.

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