Almost every dead generator I’ve put my hands on died from neglect, not from wearing out. Stale fuel, dirty oil, a choked air filter — cheap, boring stuff that takes minutes to stay ahead of. This page is the whole maintenance picture in one place: what to do, when to do it, and the guides that walk you through each job.

The Maintenance Schedule

Tape this to the shed wall. Hours are engine run hours; if you barely run the machine, go by the calendar column instead — time kills fuel and oil even when the engine sits.

Task	Run Hours	Or By Calendar
Check oil level	Every use / every 8 hrs	Before every start
Change oil (first break-in)	20–30 hrs	—
Change oil (ongoing)	50–100 hrs	Every season
Clean / inspect air filter	25–50 hrs	Every season
Replace air filter	100–300 hrs	Yearly if dusty
Check / gap spark plug	100 hrs	Yearly
Replace spark plug	200–300 hrs	Every 2 years
Fuel stabilizer in tank	—	Any time gas sits 30+ days
Run under load (exercise)	—	20–30 min monthly
Drain carb / run dry for storage	—	Before any 60+ day sit

Oil: The Cheapest Insurance You Can Buy

Small air-cooled engines run hot and shear oil down fast — that’s why the interval is 50 to 100 hours, not the 5,000 miles you’re used to on a truck. Most portables take 10W-30 conventional, and the whole job is a drain plug and about 20 minutes. My full walkthrough covers the type, the amount, and the break-in change most owners skip: Generator Oil Change: What Type, How Much, and How Often. And if your unit keeps shutting down on the low-oil sensor even with a full crankcase, that’s a known issue with its own fix — low-oil shutoff tripping with oil full.

Air Filter: Clean It or Replace It

A dirty filter chokes the engine — rich running, black smoke, bogging under load, hard starts. Foam elements get washed and re-oiled; paper elements get tapped out or replaced. I break down which one you have and what to do in Generator Air Filter: Clean It or Replace It?

Spark Plug: Ten Minutes a Year

Pull it, read it, gap it, and you’ll know more about the engine’s health than any gauge will tell you. Black and sooty means rich; oily means trouble; tan means happy. The full check-gap-replace routine is here: Generator Spark Plug: How to Check, Gap, and Replace It.

Fuel: Where Most Generators Actually Die

Gasoline starts breaking down in about 30 days. The varnish it leaves behind plugs the carburetor’s tiny jets, and the machine that ran fine in spring won’t start in fall. Stabilizer in every can, and either drain the carb or run it dry before storage — my storage routine is in How to Store a Generator for the Off-Season. Already too late and it won’t start? The fix is usually a carb cleaning: How to Clean a Generator Carburetor.

Exercise It Monthly

On the flightline we never let a backup system sit untested, and your generator deserves the same discipline. Once a month, start it and run it 20 to 30 minutes with a real load plugged in — a space heater or work light, not idle. That burns off moisture, keeps carb passages wet with fresh fuel, and proves the machine will actually be there when the storm is. Idle-only running lets moisture sit in the windings and does half the job.

Generator acting up right now?Run the Fix My Generator diagnostic — pick your symptom and I’ll walk you straight to the fix. →