What Is Non-Oxygenated Gas, and Should Your Boat or Sled Run It in North Dakota?
Non-oxygenated gas is gasoline with no ethanol blended into it. At most North Dakota stations the regular pump is E10, which means up to ten percent ethanol, and the non-oxy pump stands off to the side with its own label for boats, small engines and collector cars. For a truck that burns a tank every week, the difference does not matter. For a Lund that sits on the trailer between walleye trips, a WaveRunner that goes into the shop in October, or a sled waiting on snow, it matters a great deal.
What "non-oxygenated" means at the pump
An oxygenate is an additive that carries oxygen into the fuel, and in the United States that additive is ethanol. Take the ethanol out and you have non-oxygenated gasoline, also sold as non-oxy, ethanol-free or recreation fuel. It is commonly offered as a premium grade, it costs more per gallon, and in North Dakota it is easy to find once you start looking for the separate pump or the sticker on the dispenser.
You may also see E15 pumps, which carry up to fifteen percent ethanol. Those pumps carry a federal warning label that says not to use the fuel in boats or gasoline-powered equipment.
Why ethanol is a problem for boats and sleds, not trucks
Ethanol attracts and holds water. In a vehicle that is driven daily, the small amount of moisture ethanol pulls in passes straight through the engine and nobody notices. Boats, personal watercraft and snowmobiles live a different life. They sit for weeks, their tanks are vented to the air, and the swing from a warm September afternoon to a frosty night pulls moist air in and out of the tank. Every cycle leaves a little more water behind.
Ethanol can only hold so much water. Past that point the ethanol and water fall out of the gasoline together and settle at the bottom of the tank, which is exactly where the fuel pickup draws from. The gasoline left floating on top has lost the ethanol that was part of its octane rating. The engine either gets a slug of water and alcohol or a weaker fuel than it was built for, and neither one starts well in May.
Ethanol is also a solvent. It loosens varnish and deposits that then travel to filters, carburetor jets and injectors, and over long exposure it is hard on older rubber and plastic fuel-system parts. The newer the engine, the better its fuel system tolerates E10. The older the engine, or the smaller its fuel passages, the more that margin matters.
When non-oxy gas earns its price in North Dakota
Before storage. The last fill of the season is the one that sits for six months. Filling with non-oxygenated gas takes the ethanol-and-water problem out of the equation for the entire winter, and a full tank leaves less air space for condensation to form.
Snowmobiles. Sleds run in the coldest air of the year and sit between rides. Water in the fuel can freeze in a line or a filter on a cold morning, and an engine fed the separated alcohol-and-water layer runs rough or not at all. Many sled owners here run non-oxy all winter for those reasons.
Personal watercraft and small engines. A WaveRunner, a kicker motor, an ice auger and a portable generator all share small fuel passages and long stretches of sitting. Clean, dry fuel is cheaper than a carburetor cleaning.
Older engines. Carbureted outboards and sleds built before ethanol blends were the norm did not get fuel lines, gaskets and floats designed around alcohol.
When regular E10 is fine
A modern fuel-injected outboard, jet boat or side-by-side that runs every week through the summer will do fine on E10 from a busy station, as long as the fuel is fresh and the owner's manual approves it. A Yamaha jet boat that goes out every weekend on Sakakawea burns through its tank long before water becomes a problem. Where ethanol fuel gets owners into trouble is not the use. It is the sitting.
How to use non-oxy gas right
Match the octane your owner's manual calls for. Non-oxy is commonly sold as a premium grade, which is fine for an engine that calls for regular. The reverse, a lower octane than the manual's minimum, is never fine.
Still add stabilizer before storage. Ethanol-free fuel ages too. Dose the tank at the rate on the bottle and run the engine long enough to pull treated fuel through the whole system.
Fill up before the unit goes into storage, not after it comes out. Fresh fuel in the tank in October beats stale fuel in May.
Buy from a pump that moves fuel. A low-volume non-oxy pump can hold older gas. A busy one turns over.
Replace the fuel-water separating filter at winterization.
What the Vallely service department sees in spring
Fuel-system concerns show up at Vallely's service departments in Minot and Bismarck every spring: hard starts, rough idle, a boat that ran fine in September and will not hold an idle in May. The fuel is often the reason. Fall winterization at Vallely runs September through November at both locations, snowmobile prep runs September through December, and the service team can advise on fuel stabilization for any powersports unit headed into storage. If a unit comes out of storage running poorly, the fuel system is the first place the factory-certified technicians look, and the sooner that diagnosis happens the less damage sits inside the engine.
Vallely has serviced boats, pontoons, personal watercraft, ATVs, UTVs, motorcycles and snowmobiles from two North Dakota locations since 1974, which means that when one shop is backed up before the freeze, the other can often take the unit.
The short version
Non-oxygenated gas is gasoline without ethanol. Ethanol pulls in water and separates when fuel sits, which is why boats, personal watercraft and snowmobiles have the problem and daily-driven trucks do not. Run non-oxy for the last fill before storage, for sleds through the winter, and for small or older engines. Match the octane in your manual, add stabilizer anyway, and bring a unit that will not start right to Vallely in Minot or Bismarck before the problem becomes a repair.
Service requests for either location go through the service appointment form on vallelymarine.com: https://www.vallelymarine.com/schedule-a-service-appointment--xservice_request
Vallely Sport & Marine. Minot and Bismarck, ND.
Frequently asked questions
What is non-oxygenated gas?
Non-oxygenated gas is gasoline with no ethanol blended in. Most regular pumps in North Dakota sell E10, which carries up to ten percent ethanol. The non-oxy pump usually stands apart with its own label for boats, small engines and collector cars. It is commonly sold as a premium grade and costs more per gallon, and it stores far more predictably because there is no ethanol to pull in water.
Should I put non-oxygenated gas in my boat before winter storage?
Yes, if you can. The last fill of the season sits for six months, and ethanol fuel in a vented tank collects water through every warm day and cold night until the ethanol and water separate and sink to the fuel pickup. Filling with non-oxy gas, adding stabilizer at the rate on the bottle, and running the engine long enough to pull treated fuel through the system removes that problem for the whole winter.
Is E10 bad for a boat or snowmobile?
Not when the engine runs regularly and the owner's manual approves it. A modern fuel-injected outboard or jet boat that goes out every weekend burns through its tank long before water becomes an issue. Ethanol causes trouble when fuel sits for weeks or months, in small-passage engines like personal watercraft, and in older carbureted engines. E15 is different: its pump label warns against use in boats and gasoline-powered equipment.
