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Generator Maintenance Tips

Manufacturers and repair pros share tips to avoid the most common mistakes.

Every product is independently selected by our editors. If you buy something through our links, we may earn an affiliate commission.

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Don't Get Burned by Wattage Ratings

Every generator lists two capacity ratings. The first is “rated” or “continuous” watts. That's the maximum power the generator will put out on an extended basis. And it's the only rating you should rely on when buying a generator.

The higher “maximum” or “starting” rating refers to how much extra power the generator can put out for a few seconds when an electric motor—like the one in your fridge or furnace—starts up. If you buy a generator based on the higher rating and think you can run it at that level, think again. It will work for a little while. But by the end of the day, your new generator will be a molten mass of yard art, and you'll be out shopping for a replacement. Here are a few of the most important things to keep in mind with a generator.

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Stock Up On Oil and Filters

Most new generators need their first oil change after just 25 hours. Beyond that, you'll have to dump the old stuff and refill every 50 or 60 hours. So you need to store up enough oil and factory filters to last a few days (at least!). Running around town searching for the right oil and filter is the last thing you want to be doing right after a big storm. Here's how to pick the best generator for the job.

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Chill Out Before You Refill

Generator fuel tanks are always on top of the engine so they can “gravity-feed” gas to the carburetor. But that setup can quickly turn into a disaster if you spill gas when refueling a hot generator, so get one of these highly review gas cans.Think about it—spilled gas on a hot engine, and you're standing there holding a gas can. Talk about an inferno! It's no wonder generators (and owners) go up in flames every year from that mistake. You can survive without power for a measly 15 minutes, so let the engine cool before you pour. Spilling is especially likely if you refill at night without a flashlight.

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generatorRadovan1/Shutterstock

Running Out Of Gas Can Cost You

Some generators, especially low-cost models, can be damaged by running out of gas. They keep putting out power while coming to a stop, and the electrical load in your house drains the magnetic field from the generator coils. When you restart, the generator will run fine, but it won't generate power. You'll have to haul it into a repair shop, where you'll pay about $40 to reenergize the generator coils. So keep the tank filled and always remove the electrical load before you shut down. Here's how to turn your truck into a generator.

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Old Fuel is Your Worst Enemy

Stale fuel is the No. 1 cause of generator starting problems. Manufacturers advise adding fuel stabilizer to the gas to minimize fuel breakdown, varnish and gum buildup. But it's no guarantee against problems. Repair shops recommend emptying the fuel tank and the carburetor once you're past storm season. If your carburetor has a drain, wait for the engine to cool before draining. If not, empty the tank and then run the generator until it's out of gas. Always use fresh, stabilized gas in your generator.

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Backfeeding Kills

The Internet is full of articles explaining how to “backfeed” power into your home's wiring system with a “dual male-ended” extension cord. Some of our Field Editors have even admitted trying it (we'll reprimand them). But backfeeding is illegal—and for good reason. It can (and does) kill family members, neighbors and power company linemen every year. In other words, it's a terrible idea. If you really want to avoid running extension cords around your house, pony up for a transfer switch ($300). Then pay an electrician about $1,000 to install it. That's the only safe alternative to multiple extension cords. Period. Check out these tips for using emergency generators

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FH11MAR_516_54_003-1200 gasFamily Handyman

Store Gasoline Safely

Most local residential fire codes limit how much gasoline you can store in your home or attached garage (usually 10 gallons or less). So you may be tempted to buy one large gas can to cut down on refill runs. Don't. There's no way you can pour 60 lbs. of gas without spilling. Plus, most generator tanks don't hold that much, so you increase your chances of overfilling. Instead, buy two high-quality 5-gallon cans. While you're at it, consider spending more for a high-quality steel gas can with a trigger control valve. Here's how to build a super safe storm shelter right inside your own home.

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FH11MAR_516_54_022-1200 generatorFamily Handyman

Lock It Down

The only thing worse than the rumbling sound of an engine outside your bedroom window is the sound of silence after someone steals your expensive generator. Combine security and electrical safety by digging a hole and sinking a grounding rod and an eye bolt in concrete. Encase the whole thing in 4-in. ABS or PVC drainpipe, with a screw-on cleanout fitting. Spray-paint the lid green so it blends in with your lawn. If you don't want to sink a permanent concrete pier, at least screw in ground anchors to secure the chain.

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FH11MAR_516_54_020-1200 generatorFamily Handyman

Close-up of concrete pier, eyebolt and grounding rod

Connect the ground wire to the grounding rod for safety and the chain to the eyebolt for security. When a small engine won't start, the usual suspects are bad gasoline, a corroded or plugged carburetor, or a bad ignition coil. Here are our small engine start up tips.

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FH11MAR_516_54_026-1200 generatorFamily Handyman

Use a Heavy-Duty Cord

Generators are loud, so most people park them as far away from the house as possible. (Be considerate of your neighbors, though.) That's OK as long as you use heavy-duty 12-gauge cords and limit the run to 100 ft. Lighter cords or longer runs mean more voltage drop. And decreased voltage can cause premature appliance motor burnout. Here are our top tips for what you can do to keep your home safe and prevent disasters.

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More information available on our site:

  • Storms do more than cause power outages. Search for “disasters” and check out our prevention tips.
  • Small-engine frustration? Search for “start up tips” and get running.
  • Survive any weather in a reinforced room. Search for “storm shelter.”
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Real World Advice From Our Field Editors

Exercise your generator
“I start my generator up every three months as recommended by the manufacturer and let it run for about 20 minutes to charge the battery for my electric starter.” – Larry Meacham

Build a generator garage
“For a portable generator, we poured a small concrete pad and basically built a doghouse over the unit that is hinged to the pad. It worked better than a blue tarp.” – Al Cecil

A door for cords
“Most people run extension cords into the house through an open window or door. But our fireplace has a small cleanout door on the outside, so I run extension cords through it.” – Charles Crocker

Unplug the freezer
“Freezers and fridges are power hogs. But you can disconnect them from your generator and free up power for other stuff. First, turn the temperature settings way down. When they reach the lower temperature, unplug them and don't open their doors unless you have to. They'll act like coolers and stay cold for a long time. Freezers usually will keep food frozen about 24 hours. During that time, the generator is free to power tools or your big-screen TV.” – Rick Granger

Here's how to heat your house when the power goes out.