Ethanol Killing Outboard Motors

[South4Scuba]

This is probably a post geared more for boat owners in the USA. If you own an outboard motor in the US, you better take precautions against gasoline with ethanol.

I have a boat with a 150 HP four-stroke Yamaha outboard motor on it. I just spent $450 getting the fuel injectors repaired (replaced with cleaned injectors). It turns out that the fuel treatment recommended by my dealer did nothing to prevent major issues caused by 10% ethanol in gasoline.

Symptoms of clogged fuel injectors are poor low speed performance. My motor would die when I tried to give it gas around the marina at slow speed. It just kept getting worse and finally it became dangerous because it would die when I needed to stop while docking my boat. High speed performance is not affected as much as low speed.

I am now using Sta-Bil fuel treatment in hopes of avoiding paying $450 every 100 hours to get my injectors cleaned. There is also an enzyme treatment available, but I haven't tried that one yet.

The US government wants to up the ethanol content in gasoline to 15% ethanol which will be deadly to many outboard motors. Be sure to treat your fuel and keep a quality filter on your motor if your supply of gasoline has ethanol. :shocked2:

 

[Peter Guy]

Is this more of a problem, less of a problem, or equal for those of us with 2-stroke (oil injected) motors? (Old Johnson)

 

[lamont]

i've seen a chainsaw that had plastic fuel filter bits that were dissolved by ethanol-containing fuel.

 

[noreastDIVER84]

The ethanol also attracts water, be sure to use sta-bil and change fuel/water separators frequently. I have seen instances where a a fuel tank was run down to a 1/4 tank and then things went dowhill from there. Turns out there was that much water in the tank.

I have been having issues with my jetski and the ethanol. I am now not running regular fuel in it, I have switched to aviation fuel, it does not have ethanol, is leaded and is about 110 octane.

 

[CuNanoTube]

Ethanol is miscible in water, in other words, ethanol and water can dissolve into each other in any proportion. This is very bad for use in marine fuel. I can think of a few drying agents you could use to remove the water from your fuel, but you would need to remove the fuel from the tank to treat it.
Plus the fact that ethanol contains less energy than the mixture of compounds that gasoline is made of. Conventional gas contains about 35 Mega-Joules per litre as compared to ethanol which contains about 21.

Also, do not put too much stock in fuel stabilizers. That is not to say they cannot help, but some are just isopropanol which is just another alcohol that can again dissolve water and make the problem worse. Sta-bil according to my google-fu is a naptha based compound, so it should not cause the problem, though I have seen other reports saying it too is alcohol based.

 

[Scott L]

Thankfully, several local marinas still only pump non-ethenol gas...

 

[fire_diver]

How is a 4-stroke outboard different from my 4-stroke car motor? I know I lose MPG with ethanol (which is why I avoid it whenever possible), but if it's damaging boat motor, is it damage car motors as well?

 

[South4Scuba]

There are similar problems with 4 cycle and 2 cycle motors. If your old Johnson motor is fuel injected then you would have similar issues. Carburetors are very good at burning water with gas. That's why having a little water in gas tanks without ethanol would eventurally burn itself out after some coughing and smoking!!

As noted above, the ethanol attracts water into the fuel tank and other parts of the fuel system. I am told it will eat older rubber-like components such as o-rings and fuel lines. It was suggested to me that a 2 micron gas filter be placed immediately outside the fuel tank so that it will grab any water that comes out. My mechanic syphoned the bottom of my tank to get any water he could out of the tank.

I have a friend that had to take her boat back to the factory to have the whole fuel tank replaced because it was made of gel coated fiberglas and the ethanlol fuel dissolved the inside of the tank. 2,000 mile round trip for a free fuel tank, but it was glassed into the floor so it was a major job.

Of course, I am speaking from the perspective of someone who didn't put ANYTHING in my tank to treat ethanol. I have learned a lesson. So far my motor is running pretty good since the repair work, but not really perfect. I'm hoping with more treatment and use it will get better.

 

[South4Scuba]

Don't worry about your car. The auto manufacturers have been preparing for ethanol for quite some time. Just make sure you don't use more than 10% ethanol unless your car states "flex fuel" somewhere on the fuel tank door or fuel cap.

 

[deeper thoughts]

I have a 250 yamaha 4 stroke. I have not had any problems in the 3 years I have owned the engine.

That being said the last few months a few gas stations now have non ethanol gas and I have switched to that.(playing it safe) With the price of gas a few cents more isnt going to kill me.