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Anyone having any problems with the ethanol 10 blend in gas? I keep hearing it kills small engines - and that you need to boost the octane - and that the ethanol separates if left for a while and soaks up water from the condensation in the gas tank. Is this real?

Thanks, Tom C

I can confirm that the ethanol will absorb water from within the tank which then gets passed thru the engine robbing some performance.

The biggest problem with ethanol isn't really burning it, it's that it attacks rubber and plastic parts in the fuel system. Especially on older machines. The rubber was never meant to withstand the alcohol.

I know that on airplanes it's a big bad no-no. I would keep that same logic for my ride..

viennatech wrote:I can confirm that the ethanol will absorb water from within the tank which then gets passed thru the engine robbing some performance.

The biggest problem with ethanol isn't really burning it, it's that it attacks rubber and plastic parts in the fuel system. Especially on older machines. The rubber was never meant to withstand the alcohol.

I know that on airplanes it's a big bad no-no. I would keep that same logic for my ride..

This is all true. Though I bet newer bikes use synthetic rubber and may have less of a problem. I can't imagine it's a problem for bikes designed after e10 became widespread.

The compatibility of the fuel line components and water absorption are the big bugaboos of ethanol.

But ethanol is an octane booster. If the pumps says 87 octane ((R+M)/2) than it doesn't matter if ethanol or not, it is 87 octane. same for other grades too.

Usual problems are with rubber products: Fuel lines, o-rings, float valve (needle valve) in carburetor, fiberglass tanks.

The ethanol dissolves these items.

viennatech wrote:I know that on airplanes it's a big bad no-no. I would keep that same logic for my ride..

The reason for that is that the average airplane fuel system was designed in the 1960s. Long before ethanol was considered as a fuel additive. As such, bikes manufactured before ethanol became common (around the mid 80s in large metropolitan areas) can have problems. When ethanol was first introduced here, I had damage to some rubber hoses and composite floats on my '69 Merc convertible. Never had any problems with bikes, even though several were built in the late 70s.

The water absorbing qualities of ethanol can actually be a good thing. With plain gas, water from condensation can slowly collect at the bottom of your tank. Eventually this can cause rust or problems running the engine if too much builds up. Ethanol in the gas absorbs this moisture and runs it through the engine in small quantities. It doesn't allow water to accumulate in any damaging quantities. Also, Mydlyfkryzis is correct about octane. Ethanol actually has a higher octane than gasoline, so there is no need to "boost" octane when it's added to gasoline.

Overall, I've heard a lot of stories about the evils of 10% ethanol in gasoline. I've lived in an area that has mandated the use of that blend for over 20 years and I've never had problems with it (other than the old Merc), other than slightly reduced fuel mileage.

I have an '09 Harley and the owner's manual says you can use up to 10% ethanol in the fuel. Good thing....that's all there is out here.