Portable generator maintenance checklist
Updated August 2026
A portable generator lives or dies on fuel discipline: run it under load for 15 to 30 minutes about once a month, change the oil every 50 to 100 hours, and never store it with untreated gasoline sitting in the carburetor. Keep it dry, and run it outdoors only, never in a garage or near windows, because the exhaust is deadly carbon monoxide. Treated well, a portable unit gives 1,000 to 2,000 run hours.
| Task | Interval | Effort |
|---|---|---|
| Start and run it under a small load | 15–30 min monthly | 20 min · DIY |
| Check the oil level and top off | Monthly | 5 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Change the oil (or after the first 25 hrs) | 50–100 hrs | $10–20 DIY |
| Clean or replace the air filter | 50–100 hrs | $5–15 DIY |
| Check and gap the spark plug | Yearly / 100 hrs | $5–10 DIY |
| Task | Interval | Effort |
|---|---|---|
| Add fuel stabilizer or run the tank dry | Before storage | 5 min · DIY |
| Store in a dry place, off bare concrete | Off-season | 5 min · DIY |
| Top up and load-test at the start of the season | Storm season | 20 min · DIY |
What neglect costs
Leave gas in a portable generator over a warm off-season and the light fractions evaporate into a varnish that plugs the tiny carburetor jets, so it cranks but will not start on the night you drag it out. That stale-fuel carburetor is the number-one failure, a $75–200 clean-or-replace that pushes an older, cheap unit toward the repair-or-replace decision. The deadlier neglect is running it in a garage or too close to the house: portable generators cause hundreds of carbon-monoxide poisonings a year, so it belongs at least 20 feet from the building with the exhaust pointed away.
Leave these to a pro
A portable generator is one of the most DIY-friendly machines you own: oil, filter, plug, and fuel are all owner jobs with hand tools. Where a pro earns money is the deeper fixes, a carburetor rebuild, a bad voltage regulator, or a pull-start and recoil that let go, typically $75–250 at a small-engine shop. The one job to never DIY is the wiring: powering a house through a suicide cord or an unsafe backfeed can kill a lineworker and burn the house, so any connection to your panel needs a transfer switch or interlock installed by a licensed electrician.
This whole checklist ships as reminders in OnOtto: every task above, on the right schedule for your home, snooze-proof.
Load this checklist as remindersFrequently asked questions
How often should I start a portable generator in storage?
Run it under a light load for 15 to 30 minutes at least once a month, more often before storm or hurricane season. That circulates oil, keeps the seals from drying out, burns off condensation, and, most importantly, confirms it will actually start when you need it. Idling it with no load for a minute does not count; give it something to power. If it has sat for months on old gas, expect a hard start and plan to clean the carburetor before you rely on it.
What kind of fuel should I use and how do I store it?
Use fresh gasoline, ideally ethanol-free, since ethanol attracts water and gums carburetors faster. If the unit will sit more than about 30 days, add a fuel stabilizer at fill-up and run the engine a few minutes to pull treated fuel through the carburetor, or drain the tank and carb entirely for long storage. Keep gasoline in approved containers, rotate it every few months, and never store fuel or run the generator indoors. Dual-fuel and propane models sidestep most of this, since propane does not go stale.
How far from the house does a portable generator need to be?
At least 20 feet from the house with the exhaust aimed away from doors, windows, and vents, and never inside a garage, shed, or breezeway even with the door open. Carbon monoxide is odorless and kills fast; a running generator too close to the house is the deadliest mistake people make with them. Put it on a dry, level surface under an open-sided generator tent if it is raining, and keep a CO alarm working indoors. Many newer models add a CO-shutoff sensor, but placement is still on you.