How to Winterize Any Motor or Small Engine

how to winterize any motor or small engine

Everyone knows you need to winterize your gas-powered equipment. Well, in Florida, it’s more of storing our generators until a hurricane comes through since the mowing season never really ends. With ethanol fuel-based issues making it even more important to know how to winterize small motors and engines, this guide will give you the simple steps to ensure your equipment starts up again in the Spring.

We have an easy process to winterize your mower, generator, or any other gas motor or engine. Each piece of equipment has slightly different requirements overall, but these steps should work for most.

How to Winterize Any Motor Step-by-Step

Step 1: Clean Up the Motor and Replace the Air Filter

Because you intend to store the motor away for the winter, we first want to clean it up. Ensure the motor itself is clean—particularly around the fuel and oil caps. Next, you want to go ahead and replace the air filter so it’s ready for next season. We like to do this at the end of the season, provided we’re storing the motor in a clean, dry environment. You can also do this at the beginning of the season if you worry the filter will get damp or dirty in storage.

Step 2: Drain the Fuel from the Tank or Run it Dry

Our goal here is to run out the fuel, so you may need to drain the tank a bit or simply run it dry at idle speed until it stalls. If you already have just a little bit of fuel in the tank, you can move to the next step.

Step 3: Prepare the Small Motor with Fuel and Stabilizer

If the tank was already dry when you started, you may need to put a little bit in to start it up. Just don’t overdo it. We only want a little fuel in the tank. Use what you have, though 89-octane makes for a better preservative fuel base than 87.

The idea is to have just enough fuel in the tank to run it and stabilizer through the system until the tank empties and the motor shuts itself off. You want the gas left in the motor to have fuel stabilizer mixed in. That’s much better than straight gas which can go bad or develop water in the line due to the presence of ethanol.

With a 4-cycle engine, add some Sta-bil or other quality fuel stabilizer to the almost-empty tank. If you’re running 2-cycle, do this before adding oil to a small fuel mix. Put just a few ounces of fuel/oil/stabilizer mix in the tank at most. Remember that 8 ounces of Sta-bil treats up to 20 gallons of fuel.

Ryobi 7000-Watt Generator RY90700oFI Sta-bil

Step 4: Start the Motor

Go through your standard starting procedure. Prime the engine (if needed), engage the choke, and pull the starter cord (or push the button on an electric start).

Step 5: Run Out the Stabilized Fuel

As with Step 2, the key here is to let the engine run at idle speed until it runs out of fuel. This step makes for the most important when you winterize your engine.

While running the engine dry gets most of the fuel out of the lines, it leaves just a little in the carburetor. That’s actually a good thing, and you don’t have to figure out a way to get it out. The fuel stabilizer you put in will let it sit just fine for a few months until you’re ready to crank it back up.

Sta-bil dosage amounts to winterize your equipment
How much Sta-bil to add to your gasoline for winterization and/or storage. We like buying one of the measuring bottles and then buy more Sta-bil in larger bulk containers for refilling as needed.

Step 6: Disconnect Any Batteries or Electrical Connections

If you have an electric start motor, go ahead and unhook the connections so you don’t drain the battery.

Step 7: Store It In a Dry and Safe Location

Let the engine cool down completely. At this point in the winterization process, you can store away your mower, generator, or other piece of equipment. Just make sure to put your equipment in a place where the elements won’t hurt it. In the Spring, you can add fuel, check your spark plugs, and (hopefully) start everything right up.

Using Ethanol-Free Fuel Makes Life Easier

Ethanol-free fuel from the pump costs a lot more than regular fuel. While research shows ethanol contributes to engine wear and encourages water retention, most professionals use standard E10 unleaded gasoline. When you run a lot of gas through commercial equipment all day long, the added expense makes little sense. You also tend to run the fuel too quickly for the ethanol to allow for much water build-up.

Using pre-made ethanol-free fuels and fuel mixes like TruFuel also works. These fuels go through much more stringent refining processes, making them more stable along with having no ethanol. Products like TruFuel can remain stable for up to 10 years in an unopened can and 2 years once exposed to oxygen.


While dramatically more expensive, you can leave this fuel in the tank over the winter with no issues. If it makes you feel better, go ahead and idle the engine until the tank is dry. In either scenario, there’s no need to add a stabilizer to the mix. In our opinion, you don’t want to run these fuels all the time, but they make sense to save time on the last mow of the season to help you put up or winterize your motors and equipment.

Final Thoughts

Using your equipment regularly might contribute the most to keeping it in top condition. At the end of the season, knowing how to winterize small motors can save you lots of hassle (and expense) when it’s time to get back to work. Hopefully, these steps helped simplify and clarify that process for you.

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