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Ethanol repair issues growing

More readers report ethanol-related engine damage

Ethanol continues to be a major cause of engine damage and other repair issues, prompting concerns about the growing use of E15.

That’s according to the latest survey of Boating Industry readers. We surveyed readers of our print and digital products about ethanol and other service department challenges in April and May. Respondents were a mix of personnel from dealerships, engine and boat manufacturers, marinas and more.

Ethanol damage increasing

p12x15-BI16JUL-MarketIntel.inddEthanol appears to be playing an even bigger role in service issues than it was just a year ago.

Eighty-seven percent of our respondents reported that their business has seen engine damage caused by ethanol. That was up from 73 percent in the same survey in April 2015.

While it may be helping drive service department business, frequent issues run the risk of driving more people out of boating.

As one New York boat dealer bluntly put it: “Ethanol makes us money … it sucks for the consumer.”

A Florida-based manufacturer echoed that:

“Ethanol is a boom for the service departments. Ethanol is a HUGE drag on our industry because it negatively affects the customers. It makes them hate boating. It ruins their day, their boat and their entire boating experience.”

And it is no small problem, either, representing a significant portion of repairs based on what our survey respondents are seeing. Fourteen percent said that ethanol-related problems are responsible for more than half of all engine repairs, while 60 percent said it represents at least 20 percent of the repair issues. Those numbers are basically unchanged from 2015.

E15 fears

From the federal government to engine manufacturers, there is agreement that E15 – fuel blends of 15 percent ethanol – should not be used in boats or other small engines. Still, there is growing angst over the issue, with 81 percent of survey respondents saying they are “very concerned” about the growing use of E15 – up from 74 percent last year. Only 2 percent – down from 7 percent in 2015 – are not concerned at all.

Most notably, many respondents raised concerns of misfueling at roadside gas stations.

Those worries would appear to be well-founded. According to a 2015 BoatUS survey, 40 percent of its members fill up their boats at a gas station and other surveys have showed even higher levels.

And in a Harris Poll study conducted for the Outdoor Power Equipment Institute earlier this year, 64 percent of American adults said they weren’t sure or didn’t pay attention to the type of gas they used. In the same survey, 66 percent said they will use the least expensive grade of gasoline whenever possible and 60 percent assume that any gas that is sold at a gas station must be safe for all of their vehicles and equipment.

Source: Boating Industry survey, April/May 2016

Source: Boating Industry survey, April/May 2016

Our respondents also don’t believe their customers are knowledgeable about ethanol, with only 3 percent saying that their customers know a lot about the issue. Nearly three-quarters think their customers either know nothing (15 percent) or only a little bit (58 percent) about ethanol.

On the other hand, most in the industry consider themselves fairly well-informed: 66 percent know a lot about ethanol issues, while only 8 percent said they know nothing or only a little bit.

Service tech challenges

More generally, we also took a look at the service tech shortage that has been so talked about in the industry as we rebound from the recession.

Of those companies that have a service department, 60 percent said it is very difficult to find qualified service technicians today. Another 29 percent said it is somewhat difficult. Only 5 percent said it was easy.

The challenge has also gotten tougher than it was five years ago, readers said. Twenty-eight percent said it is much more difficult, while another 32 percent said it was somewhat more difficult. Still, 36 percent said it wasn’t any more difficult than it was five years ago and 4 percent said it was actually easier.

Source: Boating Industry survey, April/May 2016

Source: Boating Industry survey, April/May 2016



  1. We continue to hear that small amounts of ethanol in gasoline is destructive to boat motors yet nowhere do we hear exactly what the problem is. These fears are not associated with automobiles while they can burn not just a 10% mixture but 85% before anything needs to be seriously modified on the engine. The main complaint with automotive use is that the manufacturers don't increase the compression ratio to make use of the full potential of the alcohol (large engines will get fewer miles per gallon with E85 because of this). For years we've added ethyl alcohol to engines with expensive fuel additives and gas line antifreeze believing it helped our situation. Racing enthusiasts burn ethanol (in higher compression engines) for extra horsepower.

    The one difference I can think of is that marine fuel tanks and engines may sit for months without being used, whereas the family car is driven daily... could it be a fuel/alcohol/water separation issue? Not very likely but just an observation.

    Why is the cause of all this frustration not being pinpointed? Why can't a boat owner or mechanic say why he believes (and can prove) it's a fuel issue? What parts in the engine are failing?

    If the sky really is falling, what evidence is there? I get tired of hearing that the less than 10% addition of octane booster is the cause of all these repairs. Why have I never seen a boating related article that not just makes the accusations but includes some specific (mechanical or chemical) evidence.

  2. Alcohol in gasoline used in boats with older fuel lines, those not manufactured with alcohol resistant linings, will suffer fuel filter clogging and potential carburetor jet clogging. There is also the issue of condensation and water attraction by the alcohol in gasoline. So while a little alcohol as in additives might be a good thing, too much as in E15 (even E10 in older 2 strokes) can causes many performance and maintenance issues. Know from personal experience, been there done that.

  3. It's good to hear some nuts and bolts examples of problems rather than just hearsay. I believe the automotive industry completely abandoned the use of butyl rubber for fuel lines in the early sixties. There should not be much of this stuff around, especially after government intervention in about '73 when it was pretty much banned in favor of stuff like nitrile, Tygon, Viton and other elastomers that have been used for hoses, seals, gaskets, etc. However, you still see butyl rubber hose being sold as gas line on the internet by overseas manufacturers. Unbelieveable!

    As far as particles of deteriorated butyl hose clogging fuel jets on older engines with carburetors, I would think any fuel filter would strain out the contaminants.

    I don't know much about water separating out, but I've had E10 sit around for months in my old truck with no signs of this as well as some old E85. Gas stations don't seem to be complaining about it in their huge underground E85 tanks. My relatives in northern states say they no longer have to use gas line antifreeze in the tractors and old machinery during the winter.

    I recognize that there still may be fuel delivery problems in the slow changing boating world, therefore, I think a cap at a safe 10% would be wise for now. This is just enough to inexpensively raise the octane rating of gasoline from the low 80's up to about 94. The government should concentrate on the science of producing E85 in more quantity and more cheaply (use plants other than low alcohol-producing corn). Those that have no qualms about their vehicle/boats using the blend, can use the E85 and everyone is happy with the insignificant 10%.

    I hope to hear other specific problems to help in my own evaluation of the situation... I have at least six engines at stake here.

  4. I have twins , I/O 305 merc 1994 700 hour. I keep on hearing about e15 problems. Thanks for the info.

  5. Gasket materials that dissolve in ethanol were still used in the 1980's. I experienced a foam gasket in an electric fuel pump, dated 1985, turn to a black sticky thick goo that clogged my carburetor jets and float bowl at a time when I needed the engine.

  6. 6 years ago my friend bought a sailboat with Atomic 4 engine. The previous owner had replaced absolutely everything in the fuel system from fuel tank to carburetor, inclusive. For 4 years we could hardly go for a sail without having engine problems necessitating a carburetor takedown while underway, not always successfully. We often had to sail into the slip. In the fall at layup time we would empty the fuel tank completely into a clear plastic 5 gal. bottle of the type used for water coolers. There would always be a layer of separated water- alcohol 2 to 3 inches deep at the bottom. For the 2015 season we located a gas station in Ulster County NY and drove 1 1/2 hours to buy non ethanol gas for the boat. After some initial problems until all the ethanol was purged from the fuel system we have not had a single problem with the engine in two seasons. It has run as smooth and reliably as the proverbial sewing machine

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