Best Fuel For Small Engines
Article by Mark Trotta
Whatever your small engine is powering - for work or for play, the gas that you put into it is more important than ever.
The Effects Of Ethanol Gas
The big problem with ethanol-blended gas is that it's hygroscopic, which means it attracts water, and can begin to break down in as little as three weeks. It also increases vapor pressure in gas, which may cause vapor lock in the carburetor. These issues are not so bad with your car or truck, but with small engines they are problematic.
Ethanol-blended gas is especially harmful for two-stroke engines like chainsaws, trimmers, and leaf blowers. The two-stroke oil remains bonded to the gasoline but not to ethanol, so part of the mixture has no oil for proper engine lubrication.
If you run your small engine regularly, you probably won't have any gas issues. But most of the time they sit for weeks and sometimes months, which is time enough for ethanol gas to break down and cause trouble.
To make matters worse, although the pump says that ethanol E10 rated gas contains 10% ethanol, federal law allows it to have as much 20% in it.
Non-ethanol fuel is far more reliable than ethanol-blended fuel. This is because it is not as susceptible to condensation, corrosion and rust issues.
Most non-ethanol gas is rated at about 89 octane, which is fine for small engines. If you can find ethanol-free gas locally at a reasonable price, buy it.
Where Can I Find Ethanol-Free Gas?
Non-ethanol gas availability varies state to state. If you happen to live near a marina, ethanol-free gas is most always available there. Websites like Pure-Gas.org can help you find ethanol-free fuel in your area.
Gas In A Small Can
Aside from having no ethanol in them, small cans of gas are convenient. Of course, they're more expensive than pump gasoline, but perfect if you don't need much fuel. For a go kart or a mini-bike, one can equals an hour of fun!
Canned Gas is available for two-stroke (pre-mix) and four-stroke engines. Popular brands to choose from include:
Canned Gas Top Brands
- VP Racing Fuel
- Trufuel (TruSouth)
- Briggs and Stratton
- MotoMix (Stihl USA)
Any of these canned gas brands will last longer and store better than any pump gas. They are pricier than pump gas, but consider that the cost offsets that of carb rebuilds and tank flushing.
Buying by the gallon saves you money, plus refilling old quart containers makes refills a little easier.
Having one or two sealed cans around for an emergency is a good idea, particularly after a hurricane and you've lost power. If you're a doomsday prepper you probably already keep a few.
Aviation fuel (AvGas) has stabilizers blended right in, which are great for the infrequent user. The properties of the additives promote fuel stability, and it's dry-gas property eliminates water in the fuel system. AvGas has a long shelf life, as much as two years.
100 vs 100LL
AvGas that is marked "100LL" has lead in it compared to lead-free AvGas. This can be safely run in any gas engine that doesn't have a catalytic converter.
Note: Aviation fuel marked 100LL is not 100 octane the way octane is calculated for automotive fuel.
Buying Aviation Fuel
I drove down to our local county airport and asked if I could buy five gallons of aviation fuel. Their requirement is that you have to supply a "wing number" from an airplane (which I couldn't do). Buying gas from an international airport is probably even harder.
Do Fuel Stabilizers Work?
Fuel stabilizers are cheap insurance against pump gas going bad. Some people add it right into portable gas cans as soon as they pump it. This helps keep the gas as fresh as possible.
- Fuel stabilizers do not help bad gas.
- They cannot alter ethanol's hygroscopic properties.
- They cannot make condensation disappear that already has formed.
- What fuel stabilizers do is help prolong gas from going bad.
Shop: STA-BIL Fuel Stabilizer
Gas Buying Tips
For lawn care equipment and other small engines, buy as little gasoline as you need at the pump, so that you run through your gas supply more quickly. A 30-day supply is ideal.
I have a separate gas jug in my garage for my small engine projects. The effort of making an additional trip to the pump is far easier than having to deal with a no-start engine.
Best Gas For Portable Generator
I keep a five-gallon Jerry Can of non-Ethanol gasoline for our portable generator.
When needed, the generator may run 24 hours or more, so I want to have enough gas on hand for for such emergencies. After several months, if the generator wasn't run and the gas not used, I pour it into my daily driver or lawn tractor gas tank, then refill the Jerry Can with fresh non-Ethanol as soon as I can.
Best Gas For Small Engines
Unless you will be using it up within a week or two, avoid buying ethanol-blended gas. Pump gas that is ethanol-free is much better for small engines. If you don't need a lot, consider canned gas, which is convenient but more expensive than pump gas.
Shop: Four-Cycle Canned Fuel
Shop: Two-Cycle Canned Fuel