How Do I Maintain a Backup Generator?

A backup generator's maintenance schedule is built around one rule: it must start when the power goes out, so it has to start every month. Manufacturers recommend running the generator under a real load once a month, long enough to warm up, burn off moisture, and charge the battery. A generator that sits unused for months develops stale fuel, a dead starting battery, and corroded contacts, and it picks the worst possible night to reveal all three.

For a portable generator, that monthly run is also the moment to plug in a real load, a space heater or a string of lights via extension cords, so the engine works rather than just idles. For a standby generator wired into the house, follow the manufacturer's test procedure, usually a monthly run of 10 to 20 minutes that also confirms the automatic transfer switch does its job.

Ethanol-blended gasoline goes stale in a few months, and stale fuel is the classic reason a generator cranks and cranks and never catches. Use fresh fuel from a reliable station, add a fuel stabilizer designed for small engines, and rotate your supply: use the stored gas for the lawn mower or the car before it is too old, and refill the generator's can with fresh fuel. If your generator sat with old fuel and will not start, drain the tank and carburetor, refill with fresh stabilized fuel, and try again before calling a shop.

Some households choose propane or natural gas standby generators specifically to avoid the fuel storage problem; those systems trade fuel management for a mandatory installation by a licensed contractor and an annual professional service. Whatever fuel you use, the discipline is the same: fresh, stabilized, and rotated.

Match the fuel program to the season so the stored supply never goes stale. Fill the generator's can with fresh, stabilized fuel before storm season, and build a rotation habit: label the can with the date, use the oldest fuel first in the mower or snow blower, and refresh the generator supply on a schedule, roughly every couple of months in storage. Stabilizer is not a one-time magic dose, it protects best when added to fresh fuel at the pump, so treat the generator can the same way you treat the car's tank. For homes with propane standby units, keep the tank gauge in view and top off before the season, and know the delivery timeline in your area, because a snow day delivery is not guaranteed during a full outage. Whatever the fuel, the rule is the same: the generator is a promise to start, and the fuel system is more than half of that promise.

Once a year, give the generator the same service a small engine deserves. Change the oil while the engine is warm, check or replace the air filter, inspect the spark plug and replace it if worn, and clean the decorative screen and cooling fins so the engine breathes. For standby units, the yearly professional service is part of the warranty and covers the battery, the transfer switch, and the auto-start controller, the parts that make a standby system different from a portable one.

Batteries deserve special attention. A generator's starting battery charges only when the unit runs, and a battery that has drained dead over a long idle season will fail at the exact moment you need the cranking amps. Test or replace the battery on the yearly service, and for portable units, charge the battery a few days before storm season and after any long idle stretch.

Placement and exhaust are safety, not preference. Portable generators must run outside, well away from doors, windows, and vents, on a dry, level surface, never in a garage or under a deck, no matter how sheltered it feels. Point the exhaust away from the house and from neighbors. Carbon monoxide from a generator is odorless and fatal, and it has ended far too many Pennsylvania storm nights.

Know what your generator can actually power. Add up the wattage of the essentials you truly need, refrigerator, furnace circulator, well pump, sump pump, a few lights and chargers, and size or load accordingly. If the generator trips its breaker the first time you run it, you have learned that lesson at home in daylight instead of in a blackout, which is the cheapest possible version of the lesson.