How to Winterize a Portable Generator: Drain It, Stabilize It, or Replace the Carb in Spring
A gummed-up carburetor is the #1 reason generators fail between storms. Ten minutes of winterizing fixes it.
The last thing I did before I put the WGen9500DF to bed last November was drain the carb bowl into a coffee can. Took ninety seconds. That little chore is the difference between a generator that starts on the second pull in April and one that turns into a Saturday morning carb rebuild project.
A gummed-up carburetor is the #1 reason generators fail between storms. Ten minutes of winterizing fixes it.
The Verdict
The best way to winterize a portable generator is to drain the carburetor, burn the fuel stabilizer through the system, and cover the unit so moisture stays out. I've seen more dead generators from ethanol varnish than from lightning strikes, and every one of them was preventable.
| Product | Price | Why it won | Why it lost |
|---|---|---|---|
 Westinghouse WGen12500DF (B07Q1DLKBG) |
$999 | Big enough to run a house, dual fuel means you can drain the gas tank and run it dry on propane | Heavy and loud, overkill for most people |
 Champion Storm Shield (B01N7E32XB) |
$145.49 | Keeps rain and snow off a running generator, real coverage | Not a storage cover, doesn't help with carburetor issues |
 Westinghouse WGen Generator Cover (B008IBO57W) |
$17.30 | Cheap, fits the big Westinghouse units, keeps dust off | Thin material, not waterproof for heavy rain |
 Generator Cover Portable Waterproof (B0GQBXDC8J) |
$16.99 | Budget price, waterproof, fits most inverter units | No vents for running operation |
 GenArmor Tent Cover (B0DN4P4FGX) |
$118.98 | You can run the generator under it in a storm | Pricey, takes up space |
 Porch Shield Universal Cover (B0719KB4XM) |
$29.99 | Mid-range price, decent waterproofing, universal fit | Sizing can be loose on smaller units |
How I Test
I don't test covers in a lab. I put them on generators in my side yard in Asheville and leave them through the winter. Rain, snow, ice, the whole thing. Then I pull the generator out in March and see what starts.
For the winterizing steps themselves, that's 22 years of rebuilding carbs that came in with "ran fine last fall" written on a sticky note. The customer was always right. The carb was always full of varnish.
Pros and Cons of the Winterizing Process
Pros:
- Costs nothing but ten minutes and a coffee can
- Prevents the most common failure mode I see in my shop
- Works on every single gas generator I've ever touched
Cons:
- You have to actually do it, and most people won't
- Fuel stabilizer is only part of the answer. You still have to run it through the system
- If the carb is already gummed, no amount of winterizing fixes it. That's a rebuild
The Process, Step by Step
Here's what I do with every generator that sits more than 30 days. This is the procedure I've landed on after 40-plus units logged in my book.
Step one: Run the tank dry or drain it.
If the unit has a fuel shutoff valve, close it and let the generator run until it dies. That burns the gas out of the carb bowl. If it doesn't have a shutoff, you're siphoning or draining the tank the hard way.
Step two: Drain the carb bowl.
There's a screw on the bottom of the carburetor bowl. Put a coffee can under it, loosen the screw, let the gas drain out. If you skipped step one, this is where the old gas comes out. You'll smell it. That's the smell of a carb that was going to fail.
Step three: Stabilize the fuel you're leaving in the tank.
If you're leaving gas in the tank, you need a stabilizer. I use STA-BIL, the regular green stuff. Add it to a full tank, run the generator for five minutes so it gets through the carb, then shut it off. That's the part people skip. They pour stabilizer in the tank and call it done, but the carb still has untreated gas in it.
Step four: Cover it.
This is where the covers come in. A generator sitting in the weather will rust, collect moisture, and grow corrosion on the terminals. A $17 cover is cheaper than a new ignition coil.
The Covers
Westinghouse WGen Generator Cover (B008IBO57W)
Seventeen dollars and thirty cents. That's the price of a decent lunch, and it's what Westinghouse charges for the universal cover that fits their big units. I've got one on the WGen9500DF out back. It's thin, it's not waterproof in a driving rain, but it keeps the dust and the morning dew off. For a generator parked under a roof overhang, that's enough.
The material is that same silver tarp stuff you see on cheap grills. It won't stop a hurricane. It doesn't have to. It's a dust cover with a brand name on it.
Generator Cover Portable Waterproof (B0GQBXDC8J)
Sixteen ninety-nine. This one's aimed at the inverter crowd, the smaller units. It's a little heavier material than the Westinghouse, and it's got a drawstring bottom so it doesn't blow off in the first windstorm. I've had one on the Generac 2500 inverter all winter and it's held up fine.
No vents, though. You can't run the generator under this thing. It's a storage cover, period. If you're planning to run a generator in the rain, you need the GenArmor.
GenArmor Generator Tent Cover (B0DN4P4FGX)
This is the one that costs real money, a hundred eighteen ninety-eight. It's a tent, not a cover. You can run a generator under it, and it's actually waterproof. I set one up over the Champion 100376 during a January rainstorm and ran the generator for three hours. The unit stayed dry and the exhaust vented out the sides.
It's big. When it's not in use, it takes up space in the shop. But if you live in the Pacific Northwest or anywhere it rains sideways, this is the difference between running power in a storm and watching your generator drown.
The zippers are the weak point. They're standard tent zippers, and they'll corrode eventually. Keep them lubricated or expect to replace the tent in a few years.
Porch Shield Waterproof Universal Cover (B0719KB4XM)
Twenty-nine ninety-nine. This is the Goldilocks option. Heavier material than the Westinghouse, vents on the side so you can run the generator under it, and a strap system that keeps it from flying off. I've got one on the DeWalt 220W inverter and it fits fine.
It's not a tent. It won't survive a generator running under it in a downpour for hours. But for overnight storage or a light rain while running, it's the best value of the bunch.
Champion Storm Shield (B01N7E32XB)
This one's specific to Champion units, but it fits the 100376 and a few others. It's a one hundred forty-five dollar investment, which is steep for a cover. The material is genuine heavy canvas, not tarp. It's got a zippered door for access to the control panel and a chimney for the exhaust.
If you have a Champion unit, this is the cover to get. If you don't, skip it. The universal options are cheaper and do the same job.
The Big Dual Fuel Question
The Westinghouse WGen12500DF (B07Q1DLKBG) at $999 is the answer to a specific problem. Dual fuel means you can run it on gas or propane, and that changes the winterizing math.
With a dual fuel unit, you can drain the gas tank, run the carb dry, and switch to propane for the winter. Propane doesn't varnish. It doesn't go bad. You can store it for years. That's the real benefit of dual fuel, not the flexibility during an outage.
The unit itself is a beast. 12,500 watts on gas, 9,500 on propane. That's enough to run a house with central heat, a well pump, and a refrigerator simultaneously. It's loud, it's heavy, and it's probably more than most people need. But if you're in hurricane country and you want to run the whole house, this is the unit.
For winterizing, the process is the same. Drain the carb, stabilize the gas, or don't use gas at all.
Should You Buy a Cover or Just Drain the Carb?
If you only do one thing, drain the carb. That's the difference between a generator that starts and a generator that needs a shop. Ten minutes in November saves you four hours in April.
The cover is secondary. It keeps the unit clean and dry, which matters for the long term, but it won't save a gummed carb. I've seen generators under perfect covers with dead carbs, and generators sitting in the rain that started on the first pull because the owner drained the bowl.
Buy the Porch Shield (B0719KB4XM) if you want a cover. It's the best value. Buy the GenArmor (B0DN4P4FGX) if you need to run the generator in a storm. Buy the Westinghouse cover (B008IBO57W) if you have a Westinghouse and you just want something to keep the dust off.
What I'm Testing Next
I've got a new batch of inverter generators coming in for spring testing, including a couple of the new dual fuel inverters that are supposed to be quieter than the contractor units. I'll log them the same way I've logged everything else. Junebug will be on the shop floor, complaining about the noise.
One note on the GenArmor tent: I've had it up for three months now and the zipper is starting to bind. I'll keep an eye on it and update this review if it fails. As of February, it's still holding up.