Impact of Ethanol-Blended Gas on Boat Engines
Article courtesy of Tom Bingham, Gold Eagle, Co.
Warmer weather has finally arrived across most of the country, and it's time to clean up your boat and get it ready for the open waters. But, before you fill up your boat's fuel tank, there are some things you should know about ethanol-blended gasoline and its impact on your boat.
Research has found that as much as 75 percent of boats serviced at the beginning of boating season require carburetor cleaning due to build-up from oxygenated fuels. Oxygenated fuel is gasoline that contains oxygen, which is predominately caused by ethanol that is mixed into today's gasoline at the pump.
How Can Ethanol Impact Your Boat Engine?
If a boat is left in storage for more than three weeks with ethanol-blended gasoline such as E10 or E15 in the tank, you could experience any or all of the following:
Phase Separation - Ethanol is alcohol-based, and alcohol absorbs moisture from the atmosphere as it sits, causing engine corrosion. As time goes by, the mixture of gas and water separate, and the water sinks to the bottom of the fuel tank, creating two separate solutions. When this happens, it's called phase separation, which is bad news for a boat engine. When a boat is first started and gets moving, the bow rises, and the water-soaked ethanol solution is pulled into the engine, which can lead to misfire and costly repair fees.
Deterioration Issues - Ethanol is a known solvent and can affect the interior of rubber hoses and cause deterioration of the materials. Tubes that run to the fuel tank overtime can become brittle, break off or flake. Broken pieces could travel through the fuel lines and eventually clog the fuel system. For boats with fiberglass fuel tanks, ethanol can also corrode and even dissolve the fiberglass resin that holds the material together, causing major issues.
What Can You Do?
Most of the country now has gasoline-blended with ethanol (E10) at their local gas stations, and finding non-oxygenated fuel is very difficult and expensive, costing as high as $5 to $8 per quart. But, before you empty your wallet and pound the pavement looking for ethanol-free fuel, there are some things you can do to prevent the side effects of gasoline that contains ethanol.
Do Your Homework - Take the time to look over all systems of your boat, especially your fuel hoses and primer bulb. Take them in your hand and feel for stiffness or signs of the hoses becoming brittle. Prime the bulb several times prior to starting your engine and visually check as well as "feel" for leaks. Sometimes leaks occur in out of sight locations. Also, smell for fumes or possible leaks. A small amount of gas fumes are common, but if you smell a very strong odor of fuel, there's probably a leak somewhere.
Fill Your Tank - If you are using ethanol-blended fuels, make sure to run your boat on fresh fuel and keep the tank 95 percent full (to allow for expansion). A tank that is nearly full reduces the flow of air in and out of the vent, which reduces condensation on the tank walls. Condensation that does form will be absorbed by the gasoline. If possible, park your boat in a shaded area during storage or at least cover the fuel tank if it's exposed. This will aid in minimizing condensation in the tank and discourage corrosion.
Add an Ethanol Treatment - In response to ethanol-blended gasoline, there are new solutions on the market to protect your engine from the damaging effects above. Ethanol treatments like Marine Formula STA-BIL include corrosion inhibitors, cleaners and fuel stabilizer to help protect your engine. At every fill-up, add a bottle of ethanol-treatment to your tank to prevent the gasoline and ethanol from separating, attracting moisture and causing corrosion. By adding a treatment at EVERY fill-up, you not only protect your system from everyday problems with ethanol, but also the long-term problems should you not be able to use your boat as often as you'd like.
Drive Your Boat Regularly - Use your boat frequently during the season to ensure your gasoline doesn't get stale in your fuel tank, which helps protect it from phase separation. If you're unable to physically drive your boat, for any extended time more than 30 days, at least make sure and start it up using a set of "muffs" available from your marine dealer and a common garden hose. Your engine should be run a minimum of 15 minutes per month to insure all fluids are warmed and circulated. This will discourage corrosion inside the engine and keep your fuel system fresh with the stabilized fuel. Tom is director of marketing at Gold Eagle Co., industry pioneer and maker of America's No. 1 selling fuel stabilizer, STA-BIL®, and 303® Products. Tom has six years of experience in the performance chemical industry and seven years in the outdoor power equipment industry and is a certified small engine mechanic.
Problem-free Fueling Tips for Boat Performance Article by Tim Banse, Marine Engine Digest
This boating season, and depending on how you handle it, fuel will either be a nagging problem or no problem at all. Here's what you need to know, along with a few tips on keeping your boat running strong all season long.
It's no secret alcohol-laced gasoline creates a boat load of problems including absorbing moisture out of the atmosphere. There's also the fact that E-5 through E-85 gasoline shelf life is notoriously short. After about a month's time the petro chemical begins to degrade into nasty gum and varnish that clogs up fuel injectors and carburetor passages.
Obviously it's common sense to avoid alcohol altogether. Do that by scouting out marinas that sell unadulterated gasoline. Ask around. That said, it's understandable that trailer boaters are tempted to pull up to a land-based gas station to top off with the less expensive road tax Regular gas. But whenever you use automotive fuel, be sure to dose the gasoline with marine-specific stabilizer before you start pumping. And no matter what the brand name of the stabilizer, before you even open the can, read the label and follow its instructions to the letter. Know that in general, the greater the concentration of stabilizer - the number of ounces added per gallon of gas - the longer the protection before it begins to sour. StarTron is a reputable product that I use. It's easy to spot on the shelf, it's blue like windshield washer fluid. Another contender is Sierra's eGuard , it too is blue, and Gold Eagle's Sta-Bil Marine Formula Fuel Stabilizer.
It's also important to know that alcohol fuel burned within three weeks, with or without stabilizer, tends to be problem free and for the same reasons your tow vehicle doesn't have an issue with the stuff. The passage of time is the enemy of E-10 and E-15. Figure on a shelf life of about three to four weeks before the fuel rots and water seeps in.
Meanwhile, back at the waterfront know that some fuel docks rather considerately treat their gasoline supplies with stabilizer (sometimes this means gas with alcohol - sometimes alcohol free) which means that when you top off dockside you don't have to go to the trouble or expense of popping the top on your own chemicals.
No matter what the fuel source one must-have accessory item is a fuel/water separator, even on those portable outboard motors rated from 2 to 30 horsepower. Costs for a portable outboard motor sized fuel/water separator filter start at about $30 and replacement elements cost about $15. An element should last a whole season, or about 100 engine hours.
Also good to know, on these miniature water/separator/filters, the filter element proper is a tightly woven 10 micron mesh that keeps tiny bits of gum (decomposing gasoline) and other particulate matter from clogging up a small outboard motor's tiny main jet and passages.
And because alcohol is corrosive, it's pretty hard on all fuel system components. Likely as not the day will come when you squeeze the fuel primer bulb and watch in absolute horror as the contents of the bowl turn black in a swirling cloud of miniscule rubber particles. That the telltale sign that the primer bulb has rotted on the inside and may soon crack wide open and spill fuel. Imagine what would have happened if the rotten rubber had flowed to the fuel injectors or carburetor jets and you didn't have the foresight to install a filter. You may also find little yellow flecks of yellow plastic which are the broken down remains of the fuel hose liner.
On larger boats with either gas or diesel engines it's also a good idea to have a competent fuel cleansing system that begins at the fuel dock. Consider pre-filtering, or pumping fuel into a screened fuel filter jabbed into the fill tube. Its specially coated wide mesh screen not only keeps big junk out of the tank, but also separates out any free-standing water. The water drops down into a sump and is disposed of in an environmentally friendly manner. The first time you try one of these out you might be shocked at how filthy fuel can be.
If your boat is diesel powered you probably already know about the fuel additives that kill microbes, the living breathing organisms that would otherwise thrive in diesel fuel. Kill them so they don't proliferate and damage the fuel system. Once again, read the label and wear gloves to protect your skin. Have a great, safe and fun boating season.
-Tim Tim Banse is a marine engines expert and has written about propulsion for Popular Mechanics, Yachting, Motor Boating, Boating Industry and other publications around the world. His current pet project is www.MarineEngineDigest.com, a source for free information about outboard motors, stern drives and inboards. Tim's articles will be seen here and in the iboats.com blog, plus always at www.MarineEngineDigest.com.