Ethanol will boost the octane rating and it is cheaper, but there are problems associated with alcohol in a gas engine:
1. Lower Energy Content
Ethanol has about 76,000 BTU per gallon compared to ~114,000 BTU for pure gasoline. This means E10 (10% ethanol) or E85 (85% ethanol) delivers less energy per gallon, leading to higher fuel consumption and slightly reduced fuel economy scienceinsights.org+1.
2. Water Absorption and Phase Separation
Ethanol is hygroscopic, drawing moisture from the air. In a partially full tank, water can accumulate and separate from gasoline, forming an ethanol–water layer at the bottom. This layer won’t combust properly, and the gasoline layer loses ethanol, lowering octane and causing knocking scienceinsights.org+1. Phase separation can render fuel unusable and may require tank draining.
3. Corrosion of Metal Components
Ethanol and dissolved oxygen in blends can produce acetic acid and other corrosive byproducts, attacking mild steel, aluminum, and zinc parts in fuel tanks, lines, and carburetors scienceinsights.org+1. This corrosion can lead to rust, leaks, and component failure.
4. Degradation of Rubber and Plastics
Ethanol is a solvent that can swell, harden, or crack rubber seals, gaskets, and hoses, causing fuel leaks and reduced efficiency Engineer Fix+1.
5. Clogging of Fuel Systems
Ethanol can dissolve varnish and debris from older fuel tanks, clogging filters, injectors, or carburetor jets Engineer Fix+1.
6. Hard Cold Starts
Ethanol’s lower volatility makes it harder to start engines in cold weather, especially in older or small engines istanamachineries.com.
7. Higher Risk for Older and Small Engines
Vehicles and equipment made before ethanol blending (often pre-2001) or small engines (lawn mowers, boats, generators) are most vulnerable due to incompatible materials and design
From Istana Machineries
I noticed a 10% increase in mpg with non ethanol gas.
So here is the trade off:
Save 7% at the pump
Buy 10% more fuel
EC
All true - which is why an ethanol treatment is absolutely required for small engines and if you expect to park a car for an extended period you should put treatment in the car’s gas tank as well.
E15 makes this worse than E10, but that’s all true for E10 as well. The problem isn’t E15 vs. E10, the problem is putting ethanol in our gas in the first place. The original reason was to reduce greenhouse emissions, or so it was claimed, but 50 years later it’s STILL not possible to produce an energy equivalent amount of ethanol that results in less total greenhouse emission than just burning fossil fuels. And that’s never going to change. We’re putting MORE greenhouse emissions in the air using ethanol.
Bickering over how much ethanol is in gas is sidestepping the issue. We need to stop subsidizing corn for ethanol.
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It ruined three small engines of mine (had to replace carburetors at $100/machine) before I bought the VERY expensive canned regular gasoline at Home Depot. Then I found a few Maverick gas stations around Coeur d’Alene sell ethanol-free gas. So you either pay $20/gallon for the canned gas or scout out a station.