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Tom Robb
04-20-2013, 11:53 AM
The local paper has a bit about small motors being damaged by E15 (E10 suposedly ok) overheating the engine. Messing up the fuel system wasn't mentioned. Spring gardening advice.

In my motorhead days we were told that alky made the engine run cooler, not hotter. Heat of evaporation or some such - which was supposed to be a/the reason Indy cars used it 100% (E100 if you will) for fuel.

I'm guessing the warning was generated by engine manufacturers' lawyers. Who knows

What say our resident chemists/engineers?

donald branscom
04-20-2013, 03:24 PM
The local paper has a bit about small motors being damaged by E15 (E10 suposedly ok) overheating the engine. Messing up the fuel system wasn't mentioned. Spring gardening advice.

In my motorhead days we were told that alky made the engine run cooler, not hotter. Heat of evaporation or some such - which was supposed to be a/the reason Indy cars used it 100% (E100 if you will) for fuel.

I'm guessing the warning was generated by engine manufacturers' lawyers. Who knows

What say our resident chemists/engineers?

I am not an engineer of gasoline fuels.

Your engine will not be damaged.
You did not tell us what kind of engine.
Carbureted or fuel injection?

The ethanol in modern fuels is mostly a problem because it has less power and
it collects moisture. You can use a product called "Seafoam" to help keep the moisture in suspension.
For small engines like motorcycles it is a real pain because the small idle jet sizes can easily get clogged up.
The idle jets are only about .013 thousandths.

Fortunately the American Motor Cycle Assosiation
is helping to keep laws like the one that would require you to buy a certain amount of high ethanol
fuel (30-40%) from passing. That could ruin your engine. The engine fuel system would have to have larger jets and a different air/fuel mixture to idle.

When ethanol(alcohol) fuels sit for 60 days the fuel can start to turn to gel.

George Ray
04-20-2013, 03:58 PM
I have had no good experiences with small engines and ethanol gas so I avoid it like the plague. Several small carbs (Honda EU-series gens) are still less than silky smooth even after rebuilds, boils and some ultrasound since I let them sit with ethanol gas, YUCK! Not good with any gas to let them sit but with ethanol gas it seems to be the kiss of gummy death to a carb.

Woxbox
04-20-2013, 04:04 PM
All so very true, but U.S. agribusiness is reaping fine profits from the legislation, so who are we to complain?

Breakaway
04-20-2013, 07:10 PM
The ethanol lobby pushes the concept that alcohol fuel is run in race engines, a demanding application no doubt, so it must be OK for your everyday engine. What they fail to mention is that race engines are run for a few hours, then torn down and rebuilt before running again. Not so with leafblowers, snowmobiles, or lawnmowers.


All so very true, but U.S. agribusiness is reaping fine profits from the legislation, so who are we to complain?

Have you grocery-shopped in the last few years? Wox, using food for fuel has driven the cost of poultry and beef quite high.

Kevin

Tom Robb
04-20-2013, 09:16 PM
All true enough, I suppose, but the given warning was about overheating which is quite the opposite from what I'd learned way back when. That (overheating) was what I found odd. The warning was from small engine mfgr's. not Exon, et al which would seem to be the opposite of what one might expect Big Oil to be saying.

As it is, even with E10, I find I need to use fuel stabilizers (Marine Stabil) in my hi-pressure washer (Kohler engines, I think) and snow blower or the carbs need cleaned every year. The normal sitting long periods idle/unused seems to be the problem.

Woxbox
04-20-2013, 10:25 PM
Have you grocery-shopped in the last few years? Wox, using food for fuel has driven the cost of poultry and beef quite high.

Kevin

It certainly has, and I've heard it has greatly reduced shipment of food to more needy nations than ours. And the kicker is, that it takes something like a gallon of petroleum to make a gallon of ethanol. Boondoggle doesn't begin to describe this disaster.

epoxyboy
04-20-2013, 11:23 PM
All true enough, I suppose, but the given warning was about overheating which is quite the opposite from what I'd learned way back when. That (overheating) was what I found odd. The warning was from small engine mfgr's. not Exon, et al which would seem to be the opposite of what one might expect Big Oil to be saying.

As it is, even with E10, I find I need to use fuel stabilizers (Marine Stabil) in my hi-pressure washer (Kohler engines, I think) and snow blower or the carbs need cleaned every year. The normal sitting long periods idle/unused seems to be the problem.
I am guessing the overheating might occur, because as the % alcohol increases, the engine is effectively running more lean. Taken to extremes, an engine running 100% methanol gobbles fuel like there is no tomorrow, because the amount of energy it contains is low compared to gasoline, and the jets need to be huge to flow enough. In a competion engine, the upside is that they can run ridiculous compression ratios to get the power, and still benefit from the cooling effect of pouring in so much fuel. Without rejetting, i cant see how a normal engine would cope very well. A modern fuel injection system can probably compensate automatically, but not a carby.

Pete

Bill Huson
04-21-2013, 07:52 AM
CORRECTION! Indy cars used to run METHANOL, not ethanol. The only legit use for ethanol is medical related and of course BOOZE! Today the PRO class of outboard racing runs their engines on methanol. A twin cylinder 250 cc (15 c.i.) 2-stroke PRO engine turning about 13,500 RPM produces around 100 horsepower and will push an outboard hydroplane over 100 MPH. The little beast sucks down close to 2 gallons of fuel for a 3 lap race ~ 4 miles.

But ethanol in gasoline kills HP fuel economy. My outboard runabout will run over 50 MPH on gas but loses 3 MPH if gas has ethanol in it. And as others have mentioned ethanol is death to small engines that sit around a lot. I hate ethanol . . .

ahp
04-21-2013, 01:50 PM
Ethyl alcohol has 2/3 the energy content of gas, and methyl, 1/2 according to Mark's Mechanical Engineers Handbook. With alcohol you will need to make the mixture richer. The gain is that ethyl alcohol is 100 octane, and you can raise the compression ratio, if that is an option.