How Do I Get My Portable Generator Ready for Winter?
A generator is only useful if it starts when the ice storm hits. Here's the fall pre-season checklist for a portable generator — fuel, oil, a test run under load, and the storage mistake that kills most of them.
Oklahoma’s winters are quiet right up until they aren’t. A line of freezing rain rolls through, ice loads down the limbs and the power lines until something snaps, and suddenly a whole neighborhood is dark for a day or three. The homeowners who sail through it are the ones with a generator that actually starts — and every November we get the same call: someone dragged the generator out for the first cold snap, yanked the cord a dozen times, and got nothing but a sore shoulder.
A portable generator is a seasonal tool that spends most of the year ignored, and that’s exactly why it fails. The good news is that getting it ready is a short, do-it-yourself job if you do it now, before the forecast turns. Here’s the pre-season checklist.
Why fall is the time to do this
A generator sitting in the garage since last winter has three things working against it: stale fuel, old oil, and a battery or recoil that hasn’t moved in months. None of those announce themselves. The machine looks fine. You find out it isn’t the moment the power drops and you’re standing in the cold yanking a cord that won’t catch.
Doing this in November — on a calm afternoon, with the hardware store still open and daylight to work in — means any problem you turn up is a minor errand instead of an emergency. Wait until the storm is already here and every small issue becomes a big one.
The pre-season checklist
Work through these in order. Most people can do the whole list in an afternoon.
- Deal with the fuel first. If there’s old gas in the tank from last season, that’s your most likely failure point (more on why below). Drain it or run the unit dry, then plan to fill with fresh fuel you’ve treated with stabilizer.
- Check and change the oil. Pull the dipstick. Oil that’s low, black, or gritty needs changing — a generator engine holds very little oil and runs hard, so dirty oil wears it out fast. Many units also have a low-oil shutoff that simply won’t let the engine start if the level is down, which fools people into thinking the generator is broken when it just needs oil.
- Look at the air filter. A filter caked with dust and grime chokes the engine and makes it hard to start. Tap it out or replace it if it’s filthy.
- Inspect the spark plug. A fouled or corroded plug is a classic hard-start cause. If it’s black, worn, or wet with old fuel, swap it.
- Test the battery (if it has electric start). Electric-start generators have a small battery that quietly dies over a year of sitting. Charge it, or be ready to fall back on the recoil cord.
- Do a real test run — under load. This is the step people skip. Start it, let it warm up, then plug in something real — a couple of lamps, a space heater, a box fan — and let it run 20 to 30 minutes. You want to confirm it not only starts but produces steady power without surging, sputtering, or dying. A generator that idles fine but stumbles under load is telling you something now, while you can still fix it.
- Check your cords and connections. Inspect your extension cords for cracked insulation or bent prongs, and make sure whatever you use to feed the house — a proper generator cord and inlet, or a transfer setup — is intact. Never run a generator into your home’s wiring through a regular outlet; that “backfeeding” is dangerous to you and to utility crews.
The fuel problem that kills most generators
If you remember one thing from this article, make it this: stale gasoline is the number-one reason portable generators won’t start. Ordinary pump gas — particularly the ethanol-blended fuel most Oklahoma stations sell — begins to break down within weeks. The lighter parts evaporate and what’s left turns into a sticky varnish that clogs the pinhole-sized passages inside the carburetor. The engine cranks, but fuel can’t get through, so it won’t catch or it fires and immediately dies.
You avoid the whole mess two ways. Either run the generator dry before storing it — shut off the fuel valve and let the engine consume what’s in the carburetor until it stalls — or treat every tank with fuel stabilizer so it stays usable for months. Combine stabilizer with the monthly exercise run and you’ve eliminated the single most common generator headache before it ever starts.
Standby generator owners: yours is a different job
If you have a permanently installed standby generator — the kind that sits beside the house and runs on natural gas or propane — most of this checklist doesn’t apply. Those units exercise themselves automatically and don’t suffer the stale-gas problem. What they do need is professional annual service: oil and filter changes, a load test, and a check of the transfer switch and battery. Fall is the right time to have that done, before the winter rush. If you’re not sure when yours was last serviced — or you’re weighing whether to move up from a portable unit to a standby one so you never have to fight a pull cord in an ice storm again — that’s exactly the kind of thing our generator installation and service team handles across the metro.
One rule that never changes: carbon monoxide
No readiness checklist is complete without this. A portable generator produces carbon monoxide — colorless, odorless, and deadly — and it must always run outdoors, well away from the house, never in a garage or on a porch, even with the door open. Point the exhaust away from doors and windows, and make sure you have working CO alarms inside. Every winter, outage-related CO poisonings land people in the hospital, and they are entirely preventable. Getting the generator running is only half the job; running it safely is the other half.
When to call a pro
Call if your generator starts but can’t hold a steady output, if it surges or dies under load, if you see scorching or smell burning at the cords or inlet, or if you’re still fighting a no-start after fresh fuel and a new plug. And call before the season if you want the connection done right — a proper inlet and interlock or transfer switch so you can power your furnace blower and essentials safely, instead of running a tangle of cords through a cracked door.
The bottom line
A portable generator is only worth owning if it starts when the ice storm hits, and that comes down to a short fall checklist: fresh, stabilized fuel; clean oil; a good plug and filter; a charged battery; and a real test run under load so you know it works. Treat the fuel right and exercise it monthly, and you skip the most common failure entirely. Do it now, on a calm November afternoon — not by flashlight when the power’s already out and the temperature’s dropping.
Want your generator setup checked, a standby unit installed, or a safe transfer switch put in before winter settles over the metro? Graco helps homeowners across Edmond, Oklahoma City, and the surrounding area get storm-ready, with flat-rate pricing you approve up front before any work begins. Call us at (405) 500-5333.
Frequently asked questions
- How often should I start my portable generator?
- About once a month, and let it run 20 to 30 minutes with something plugged into it so it's working under a real load — not just idling. Monthly exercise keeps the carburetor clear, the battery or recoil in shape, and the engine's seals from drying out. A generator that sits untouched from one ice storm to the next is the one that won't start when you finally need it.
- Why won't my generator start after sitting all summer?
- Nine times out of ten it's the fuel. Ordinary pump gasoline — especially the ethanol-blended fuel most Oklahoma stations sell — starts breaking down in a matter of weeks and leaves a gummy varnish that clogs the small passages in the carburetor. The engine cranks but won't catch, or starts and dies. That's why draining the fuel or treating it with stabilizer before storage matters so much, and why a no-start after months of sitting is so common.
- Is it safe to store a generator with gas in the tank?
- Only if that fuel is stabilized, and even then it's a short-term plan. Untreated gas goes stale and gums up the carburetor; stabilized fuel buys you several months. Many people instead run the generator dry — shut off the fuel valve and let the engine burn off what's in the carburetor until it stalls — so nothing is left to varnish. Either approach beats parking it with a tank of old, untreated gas.