The on-the-water location for ethanol-free gas at Clear Lake: Marina Bay Harbor Marina.
Imagine the ill-advised runner who eats a dozen donuts before jogging a marathon. They’re running a blend of inferior compounds through their fuel lines–sugar and corn syrup. Twelve miles into the race, their acceleration lags and power falls behind. They go home and a dozen donuts – less lasting as a fuel – break down, sludge up their fuel tanks, and put their engines into nap mode.
This is the “pros and cons” conversation of ethanol versus ethanol-free gasoline for boats, and it becomes even more important for the center-consoles so prevalent on the Gulf Coast that are ready to surge out and cover hundreds of miles in a day.
Pure gasoline versus alcohol. Knowing the pros and cons of ethanol-free gas versus ethanol is like knowing the vitamins you need to live. For your boat, the right nutrition is the difference between stress-free weekends and a looming engine replacement.
Marina Bay Harbor Marina, where CCA Texas Tournament boaters stop for ethanol-free gas
The benefits of ethanol-blended gasoline for boats
Ethanol is synonymous with grain alcohol. Amidst its industrial history, it’s been used as an additive, a solvent, a disinfectant, and an old-school anesthetic. It is an organic-based compound derived from the fermentation of sugar crops like sugarcane and corn. In a science lab, you’d see it labeled as CH3CH2OH. In the grocery store, you have only to look at the liquor aisle.
Ethanol is a “miscible” solvent, a water-soluble compound, which is the Achilles heel of the product: while pure gasoline will not absorb moisture in your boat engine, E10 (10% ethanol gasoline), according to a University of Nebraska study, will hold up to 0.41% water. Say you own the 2025 Cobia 220CC 22-footer with a full 89-gallon tank using ethanol-blended gasoline, about a third of a gallon in there might be sloshing water, or roughly the equivalent of two twenty-ounce water bottles.
Ethanol-blended gasoline is desirable environmentally as a renewable fuel source. The production of it creates no net carbon dioxide emissions, although its eco-friendly status can sometimes be criticized as it’s produced by industrial farms that may use harmful pesticides to grow the needed crops. It also carries a cheaper price per gallon.
The benefits of ethanol-free gasoline: Better power, better mileage, lower repair costs
One blend of ethanol-free gasoline is most desirable – and often necessary – for boaters driving high-performance, high-horsepower powerboats. That’s 93 octane non-ethanol gasoline.
Ethanol includes 35 percent oxygen by weight. This improves the fuel’s ability to burn with less of an environmental footprint – the trade-off is that one gallon of ethanol contains about one-third of the energy of a gallon of straight gasoline. Using E10 gasoline, this translates to about a 3% decrease in fuel economy. This energy deficit is recognized by some boaters via a lag in acceleration. Let’s stick with that 2025 Cobia 220CC example – that boat might get four miles per gallon on an 89-gallon tank. That’s not an enormous ding to the wallet if you aren’t using E85 gasoline, but the costs will reflect in maintenance and a lag in power during your annual Gulf Coast Poker Run.
Engines that regularly use ethanol-blended gasoline may need the fuel lines changed as they erode. For older vessels, this extends to the carburetors. An extreme lack of engine hospitality might result in the loosened debris in your fuel tank causing catastrophic engine failure – that, of course, is the worst-case scenario. The solution to not worry about any of this is to call your local marine service center and schedule routine maintenance. If you’re a South Texas boater, the trusted center where boaters drive from Houston and beyond to service their boats is the Marina Bay Harbor Marine Service Center in Clear Lake Shores.
A high-performance powerboat with twin Mercury 450R outboards feeds its fuel tank at Marina Bay Harbor Marina
How ethanol-blended gasoline can do nasty damage to your boat
Ethanol naturally absorbs moisture. It’s a solvent. It’s also corrosive. Mixed in your fuel components, dormant ethanol-blended gasoline will corrode fiberglass, rubber, and plastic, and rust out metal components.
Humidity blended with ethanol is like watching the inside of an unwashed fish tank grow green algae. The Gulf Coast of South Texas often produces days with a steady 75% humidity. In a high-temperature, high-humidity environment, E10 gasoline won’t go into “phase separation” as fast, when the water and ethanol break away from the fuel and settle to the bottom of the tank. When the temperature lowers with the same high humidity, it produces a sludge. Think as if you opened a jar of honey and drizzled it into your Boston Whaler fuel tank.
As a solvent, ethanol disengages debris from the walls of a boat’s fuel tank. The loose debris can then clog fuel lines and sit in the tank like gum. The ethanol’s stability, translated to your fuel tank in storage, is that it will degrade and break down in about 90 days. In contrast, boaters quote ethanol-free gasoline storage as lasting for anywhere from six months to indefinitely.
So your boat runs ethanol gasoline and it sits: Use an additive, run the engine
Boaters who use ethanol-blended gas can combat the more corrosive fuel elements with a deeply held boating-world secret:
Run the engine.
Okay, so it’s not that secret. If you’re driving a 2024 Midnight Express all summer with smooth-burning 93 octane, you probably don’t worry so much about letting fuel sit. Boaters who might only step foot on their vessel on the Big Three weekends (Memorial Day, Fourth of July, Labor Day) run the risk of inviting corrosion and sludge from leftover fuel that sits for weeks or months. The homegrown approach is to make sure all that fuel is burned off before you put the boat in storage.
The complementary piece of boat care is to give your boat a marine fuel stabilizer. STA-BIL 360 Protection is regarded as one of the most dependable and popular marine fuel additives. It’s almost as popular as the tried-and-true “red STA-BIL,” or STA-BIL Storage blend. Yamaha Yamalube is also a dependable stabilizer made by one of the world’s largest outboard manufacturers, and some boaters swear by Sea Foam’s fuel treatment.
No water, no contaminants: Use a marine fuel water separator
Think of the skim net you’d use in a summer pool to remove the leaves. That’s a marine fuel water separator for your fuel tanks. The filter serves as a gatekeeper for the tank: as the fuel enters, the water (being denser than gas) sinks to the bottom of a collection bowl in the filter. Dirt and debris are retained out of your tank by the filter media.
These “spin-on” filtration systems resemble a gallon paint can, sometimes with a clear bowl attached to the bottom. They are highly inexpensive and may save your engine someday – Yamaha’s fuel water separator, for example, costs about $14.
Photo: Yamaha
A handy boater can install a fuel water separator themself – how to install a fuel water separator requires a few tools like a cordless drill, screwdriver, and marine-grade sealant. Boating Magazine published a convenient guide for how to install a fuel water separator, and if you don’t want to worry about the time or the know-how to install it yourself, contact your local marine service center. Texas Saltwater Fishing Magazine recommends changing a filter about once per year or every 100 hours.
Marina Bay Harbor Marina: The Clear Lake fuel stop for 93 octane ethanol-free gasoline
Marina Bay Harbor Marina: Where Gulf Coast boaters make pit stops for bait and ethanol-free gas
The largest tournament on the Texas coast each year is the Coastal Conservation Association’s (CCA) STAR Tournament, a summer-long adventure that rewards anglers with life-changing scholarships and gorgeous truck and boat packages. For those that don’t win, they get the chance to compete in waters teeming with sheepshead and redfish.
Seventeen Texas locations from Orange straight down to Port Isabel are designated as official CCA weigh stations. Marina Bay Harbor Marina, nestled in a cove in Clear Lake Shores, Texas, is one of them. To support its sportfishing enthusiasts, those who start fishing at the light of dawn can get their 93 octane ethanol-free gasoline earlier than any other angler on the Coast: Marina Bay Harbor Marina’s bait shop and fuel docks open at 6 a.m. on Fridays, Saturdays, and Sundays.
A Clear Lake boat fuel debate: ethanol-free versus ethanol-blended gasoline
Some boaters may wish to go with E10 or E15 gasoline specifically for the environmental aspect: a clean-burning fuel option with net zero carbon dioxide emissions. Those who seek an edge in gas mileage, power, and longevity may stick to traditional ethanol-free gasoline. For the boaters of Galveston Bay, this often looks like 93 octane gasoline from Marina Bay Harbor Marina.
Know your engines like you know your own diet – give them the fuel they need.
Marina Bay Harbor Marina is the premier South Texas location for boat storage, boat maintenance, bait, and ethanol-free gasoline. Our service technicians are certified as an official location for Yamaha, Suzuki, and Mercury Marine engine work. Our highly experienced and agile service team working within a sophisticated dry storage facility has made us a consistently excellent destination for storage and service since 2003.
Give us a call to schedule a service appointment at 281-549-4772 or fill out our convenient service request form. Those looking for the place to get live shrimp and ethanol-free gasoline on Clear Lake? Stop in anytime.