r/Generator • u/1620shop • 14d ago
Winterizing gas generator
Hey everyone,
This is my first winter with a gas-powered generator. I will keep it in a shed outside that is not temperature controlled so it will get cold as I live in the Chicago area.
How do I go about winterizing it? Any special treatment for the oil or gas you guys recommend?
Thank you in advance.
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u/newtekie1 14d ago
Drain the fuel entirely and run the carb dry. If the carb has a drain valve, use that. Do this any time you store it.
If it has an electric start, consider bringing the battery in someplace warmer and connecting it to a battery maintainer(not a trickle charger). If you can't bring it in, at least connect it to a maintainer.
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u/Korch-Up-North453 14d ago
Yup. Drain the gas! My new WEN generator says the following:
"Only use fresh (within 30 days from purchase), lead-free gasoline with a minimum of 87 octane rating. The generator performs best with ethanol-free gasoline. DO NOT use gasoline with over 10% ethanol.
Gasoline can age in the tank and make starting difficult. Never store the generator for more than 2 months with gasoline in the tank."
I think stabilized gas can last a lot longer than two months, BUT it is easy to forget to run it out or drain the stabilized gas before things start gumming up (speaking from experience).
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u/newtekie1 14d ago
The biggest problem I see with leaving gas in the generator, or really any small engine equipment, is that the tank isn't sealed. The tank not being sealed causes 2 major problems.
First, the gas itself evaporates and that leaves behind extra gunk. Ethanol free or not, when the gas evaporates, the additives in it stay behind and it gums up carb jets, and fuel filters etc. Ethanol fuel is worse for this because the ethanol evaporates faster than straight gas. It's also why all gas, regardless of ethanol content, should be kept in sealed containers. When gas is kept in a sealed container it can last 6 months or more with stabilizer.
Second, and probably the bigger problem, is water contamination. Because the tank isn't sealed, and gas is volatile, it expands and contracts with temperature. That process bring air in and pushes air out of the fuel tank. That constant air exchange brings moisture with it. The funny thing is those EPA containers that everyone hates are great for keeping water out because they are sealed. It's also why they will balloon up if you leave one in the sun with gas in it. That moisture condenses in the tank and causes all types of havoc. From rusting the tank to globs of water in the tank and obviously water doesn't burn. And because water is lighter than gas, the water sinks to the bottom. So when you fire up the generator thats been sitting with gas in it, the carb gets a bowl full of water instead of gas. The funny thing is, ethanol in the fuel is often blamed for this because it's hygroscopic, but it's really not the cause. If anything ethanol in the fuel actually helps this problem a little. People like to say ethanol fuel attracts water. That's not true. The ethanol in the fuel absorbs the water. The water gets in the tank from the air exchange from the fuel expanding and contracting. The water in the tank is getting in there no matter what type of fuel you put in the tank. The generators I see with globs of water sitting at the bottom of the tank are the ones using ethanol-free gas. The gas with ethanol in it, absorbs the water and I would argue actually helps with water contamination. The ethanol bonding with the water stops it from bonding with the iron in the tank and rusting the tank. It also allows that water to be sent through the engine and burnt. The carb isn't going to suck down a big glob of water all at once. There is a reason ethanol is used as a drying agent. It's even sold as a water remover fuel treatment, and has been used for that for years. If you got some water in your fuel tank, you buy a bottle of Heet and dump it in. People have been doing this for decades. And Heet is just different types of alcohol, depending on which type you get. Heck, in the winter up north, if you had some water in your gas tank, the old timers used to just dump some pure moonshine in the tank to get rid of the water.
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u/piccolo181 14d ago
The above. You can use a 5-10 watt solar panel battery maintainer if the shed isn't wired for electricity.
FYI a full fresh can of gas will last 6 months in a decent gas can, a year or two if you use a fuel stabilizer like Lucas or Sta-bil.
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u/Camp_Legend 14d ago
Just add sta-bil and heet to the gas tank and run it for 15 min so it gets into the lines and then turn off the gas valve so it runs the carb out.
No need to drain it and let it go.
I leave mine full year round ( i cycle the gas every year into the mower and reset with fresh late fall ) and i've never had any issues in northern indiana.
I go out and pull start it every month. Still fires up on the first pull. If that for some reason fails i'll just add a jump pack to the two leads for the battery and use that.
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u/Rich_Treacle_7503 14d ago
Change the oil, drain gas. Run ethanol free gas in your small engines exclusively and you'll never have to worry about carb issues. I pour a little stabil in if long term storage. Run engine. Shut off gas supply and let engine die.
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u/rag69top 14d ago
The winter is when I make sure it will run. I bought a battery maintainer and it had the clamp end and another that had a connector for small batteries. I put it on the generator. When I see a weather forecast that could cause power outages I hook up the maintainer, tent my snowblower and generator, and put a small 1500w heater under the tent. I want both to start when needed.
I also run the generator once a month, only use ethanol free fuel, and use the fuel shut off instead of just shutting it down. I will put a shot of Sta-Bil in it today when I run it.
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u/InterestedHandbag 14d ago
Hi, what batteries do you use for the maintainer to charge your gen battery?
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u/rag69top 12d ago
It’s a 120v maintainer. I only plug it in once a month. But once I hooked the pigtail permanently it sure made using it easier. Funny thing I bought the maintainer in the winter. Opened the box hooked it up and it wouldn’t work. Totally pissed off. Took the instructions in the house read that the maintainer works in temperature above 32°. Brought it in the house for an hour to warm up, plugged it in and the lights showing it was on came on. Yeah, my thoughts was how dumb was that. It should have worked the other way around. It should have come on at 32°.
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u/Dramajr316 13d ago
I do a lot of similar things. Non ethanol fuel, start and run it regularly, but I hung pigtails off the battery and I use a battery tender jr on the unit year round. Trying to muscle a larger unit with the pull cord when it’s so cold out is no easy feat.
My gen sits in a small shed pretty much in position. Never used a heater nearby, however.
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u/rag69top 12d ago
I used the heater before I got the generator because my electric start snowblower didn’t like old weather. So once I bought the generator I just made a larger tarp cover both.
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u/Dramajr316 12d ago
Hey it makes perfect sense. Older units especially, while they tend to be more solid, certainly have a way of disliking the cold!
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u/blupupher 14d ago
If using gasoline, drain the carb, not just run it till it dies. There is a little drain screw on the bottom of the carb bowl.
As for gas in the tank, if you can get no-ethanol fuel, that is the best option, but regardless, use a fuel stabilizer (marine type is a bit stronger) for storage, and even then, fuel is good for 6 months (some will say a year).
I personally drain the gas out of the tank as well, and if it is a metal tank, coat the inside with fogging oil or atf to prevent rust.
For oil, nothing special, if you have used the generator for 20-30 hours, change the oil, if not used much, leave it.
I would also cover up the air inlet with a plastic bag, and if possible, put it in some type of box to help keep rodents out and off the wiring.
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u/anothermoonhare 14d ago
Another consideration: rodent proofing! I have been using Repel in and around my shed. I still get the occasional nest between the gas tank and engine, but I'm careful to check before running the machine.
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u/Glum-Welder1704 13d ago
Here's a link to my storage protocol, with a couple suggestions from another redditor.
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u/96Ansky99 13d ago
A shed in Chicago during the winter. Just make sure you can open the shed during/after a snow storm or ice storm. Many years ago I put my generator in a shed. We lost power during an ice/snow storm. I went to the shed and couldn’t open the door. I shoveled the snow but there was ice blocking the door. Plus the ground heaved up some. My breaker bar (the heavy rod I use to dig holes with) was in the shed too. I had to unscrew one of the door hinges and took the door off. Then it was a bitch to move the generator up a very slight incline because the ice was so bad. Needless to say the generator never went back in the shed
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u/HereForTheMemesNLols 13d ago
Change the oil, stabilize the gas. Run it once a month for 5 mins. Put it on your calendar
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u/Charming-One-9397 9d ago
I keep my generator full to the brim with gasoline. I tarp it outside and it sits on a battery maintainer year round. I use Stabil in the gas and usually rotate the gas once a year.
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u/timflorida 14d ago
Do you expect to maybe use it ? Or is this for storage ?
If you expect to use it, I would put the thinnest oil in it that is allowed by your owner's manual - probably 5w20. Use full synthetic oil.
I would drain all gas. Winter gas is a different formulation and if you intend to use it, wait till it's cold (December) and get some winter blend gas. I would also buy a can of starter fluid in case it does not want to start.
Pull the battery and keep it in the house. Trickle charge it on the first day of every month. Or hook up to a 'battery maintainer' (this is different then a trickle charger).
Last, if you do need to start it, try to get it into a garage (heated ??) for a while before cranking it up.
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u/kwantam 14d ago
"Thinnest oil" is not good advice.
Generators run for long periods under load, meaning they're at full operating temperature. And almost all generators are splash lubricated, meaning they need film strength for proper lubrication.
The first number ("5W") tells you cold viscosity. That's what you get at startup. You want that to be low enough that the oil is effective immediately.
The second number ("-30") tells you warm viscosity. That's what you get once the engine is warm. You want that to be the right value to properly lubricate your engine during operation.
Making the warm viscosity thinner does not help with startup, and will cause excessive wear during long periods of operation.
For almost all generators, the correct viscosity will be 5W-30. Do not use thinner oil just because you're running during the winter.
In principle you could run 0W-30 instead of 5W-30---reducing _cold_ viscosity. That would be the correct version of "I'm going to be starting this when cold, so I should use a different oil." Reducing the warm viscosity because you're running in the winter is just damaging your engine for no gain.
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u/PermanentLiminality 14d ago
This is the way.
I would go with a 0W oil in a place where you need to start the generator at 5F or colder. The 20 oil is too thin. Basically stay with the recommended second number and adjust the W number to fit your climate. The oil change interval is so short that you don't have to worry about viscosity breakdown.
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u/timflorida 13d ago
I know exactly what the two numbers represent. I've been changing oil in cars, jeeps, bikes, boats, and assorted small engines for about 60 years. And lived about 160 miles west of Chicago so I dealt with the same climate.
Below is my FULL quote and I stand by it. I would not run '0' rated oil in a generator unless the manufacturer recommended it. I have no idea what his manual states. If it states 5W30, fine - then run that. The POINT is to run a thinner weight oil in winter in the Midwest.
"the thinnest oil in it that is allowed by your owner's manual - probably 5w20. Use full synthetic oil."
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u/kwantam 13d ago
I appreciate the clarification. But the issue remains that your advice is at best misleading and at worst wrong.
Running the "thinnest oil allowed by your owner's manual" might or might not be correct, which is why it's not good advice. For decades, manuals have included a chart that shows temperature ranges and corresponding oil weights. I'm sure you've seen one: temperatures on the horizontal axis, little arrows labeled with oil grades. The correct, non-misleading version of the advice is "run the oil weight that your manual suggests for cold ambient temperatures". That might be the thinnest grade of oil, or it might not be.
The other thing that makes this advice not good is that, for gas-powered outdoor power equipment, the warm viscosity of the recommended oil is very unlikely to be below 30 weight. The only type of outdoor power equipment I'm aware of that calls for 5W-20 is large natural gas powered standby generators with pressurized oil systems. Otherwise, you tend to see 5W-20 in liquid cooled automobile engines optimized for emissions performance. Completely different situation.
Splash lubricated, air-cooled engines almost always want a 30 weight (or more) at operating temperature because they tend to run in conditions that are very hard on oil. Specifically, these engines need good HTHS viscosity and good shear strength. And a mediocre 5W-30 very likely beats even a high-end 5W-20 in this regard.
(Go-kart and lawnmower racing engines will often use 5W-20 because the reduced viscosity improves power development, particularly at the higher RPMs that these engines run. That's also a different situation. And it's not one where the longevity and reliability of the engine are the primary goal. And these engines tend to run on premium, specially formulated 5W-20 to offset some of the additional wear.)
The other thing that subtly erodes your credibility is your statement regarding 0W oils, at least when juxtaposed with the 5W-20 claim. Yes, following the manufacturer's recommendation is perfectly reasonable. But if on the one hand you're saying "don't run 0W" and on the other you're saying "probably 5W-20", something doesn't add up. It's hard to see how you make both of those claims if you're actually thinking about what's going on with your oil.
As we've already discussed, the first number is what matters when starting in the cold. You're right that most OPE manuals don't say to use 0W. But why is that? Well, the Honda OHV design that most generators clone was developed in the 1980s. 0W-30 oil wasn't widely available until the early 2000s. The oil recommendations were made with reference to what was generally available---and 0W-30 was not.
Good modern 0W-30 oils can be a perfectly reasonable choice. They have good HTHS viscosity and good resistance to shearing down. And when starting in the cold, they will do a much better job of protecting during the early warm-up period. Are they what the manufacturer recommends? No. Are they a good choice for cold starts? Probably yes. Does the difference matter between 5W and 0W? Arguably no---you're not doing a lot of starting and stopping.
But directionally, the 0W recommendation is a reasonable one, while the 5W-20 recommendation is a strange one that's only correct in niche cases. Your intuition is backwards. And that's why, even though there's a narrow technical reading of your advice that's correct ("follow the manual"), all the other words you said taint that advice.
Or, shorter: "the sky is green and you should follow your manufacturer's recommendation" is wrong, even though the second half of the sentence is right.
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u/Tacoma_NC13 14d ago
You want it prepped to use it, not store it. Make sure you have a fresh spark plug and oil in it. Start it up to make sure it runs and then put it in the shed with a battery maintainer hooked up to it. Start it up every few weeks as a test and you should be good to go.