A generator is the one piece of preparedness equipment that reliably fails because it was never used. Fuel sits, oil degrades, a carburetor gums up, and the failure surfaces at the worst possible moment — during the outage, in the dark, with no parts store open.
The fix is unglamorous: a break-in procedure once, then a short routine a few times a year.
The Break-In Period (First 20-30 Hours)
New engines shed metal as the piston rings seat, which is why the first oil change happens long before the normal interval.
- Run it at light load for the first hour, then vary the load through the break-in window — don't let it sit at idle, and don't immediately run it flat out.
- Keep loads under about half capacity for the first few hours.
- Change the oil after the first 20-30 hours (or per the manual — some specify 5 hours). Expect fine metallic sheen in the oil; that's normal on a first change, and it's exactly why you dump it.
- Check the oil level before every single start afterward. Low oil is the second most common cause of a dead generator, and most units have a low-oil shutdown that will simply refuse to run.
The Upkeep Rhythm
| When | Do this |
|---|---|
| Before each use | Check oil, check fuel level, inspect for cracks or leaks, confirm exhaust direction |
| Monthly | Start it and run it under load for 20-30 minutes |
| Every 50 hours or seasonally | Change oil, clean the air filter, check the spark plug |
| Yearly | Replace the spark plug, inspect the fuel lines, test the transfer switch (standby units), and have a standby unit professionally serviced |
| Before storm season | Full fuel, fresh oil, charged battery (standby), and a dry run with the house loads connected |
Running it under load matters more than people expect. Idling a generator in the driveway every month keeps the engine turning but doesn't exercise the alternator or reveal a problem with the outlets, breaker, or transfer switch.
Fuel Is Where Generators Die
Ethanol-blended gasoline begins degrading in about 30 days and can phase-separate in a few months, leaving a corrosive layer that attacks carburetors and fuel lines. That's the single most common reason a stored generator won't start next season.
- Add a fuel stabilizer to any gas you keep, and treat it at fill-up rather than in storage.
- Rotate your stored fuel — use it in the mower or car and refill, so it never gets older than a few months.
- Shut off the fuel valve and run the carburetor dry before storing for the season. This one habit prevents most spring no-starts.
- Propane and natural gas don't have this problem, which is a real argument for tri-fuel or standby units in a long-term plan.
- Store fuel safely: approved containers, away from the house, never in a basement or attached garage if local rules forbid it.
Storage
Keep the unit dry, level, and covered — moisture in the fuel system and condensation in the tank cause more damage than cold does. For a standby generator, the battery is the weak point: keep it on a maintainer, because a standby unit with a dead battery is just a large lawn ornament.
When It Won't Start: The 60-Second Diagnosis
Check these in order — it's almost always one of the first three:
- Oil level — many units won't fire with low oil.
- Fuel valve and choke — closed valve and wrong choke position account for a huge share of no-starts.
- Old fuel — drain and refill if it's more than a few months old.
- Spark plug — pull it, check for fouling, replace (cheap and easy).
- Air filter — a clogged filter makes it run rough or stall under load.
- Battery (electric start) — charge or replace.
Safety, One More Time
Never run a generator indoors, in a garage, in a shed, or within 20 feet of doors, windows, and vents, even with the garage door open. Carbon monoxide is odorless, and it kills people in exactly this scenario every storm season. Put a CO alarm on every level of the home — our heating without power guide covers why this is the number one indoor risk during an outage.
When It's Time to Replace Rather Than Repair
If a unit has sat for years with old fuel in it, needs a carburetor, and is out of warranty, the repair bill often approaches the price of a new unit. Our best generators guide breaks down what's worth buying at each budget, and if you're weighing a permanent install, whole-house vs. portable and the installation cost by state pages cover the real numbers.
Use our free Generator & Home Battery Calculator →
Related reading: Power Outage Checklist, Best Home Generators of 2026, and How to Heat Your Home Without Power