From the Shop: Know your fuels
1 Jan, 2007 By: Harry Smith Landscape ManagementFuel prices and alternative fuels have been in the news for months. Gasoline and diesel prices have a direct effect on our bottom lines. Just about everything we operate needs one fuel or the other. Careful routing of our fleets, reducing the time our equipment spends idling instead of working and keeping our equipment tuned can save us fuel dollars. But what is the effect of some of the additives and alternate fuels we're getting at the pump?
In many places we can buy biodiesel, 10% ethanol gasoline (E10) and even E85 fuel that is 85% ethanol and a mere 15% gasoline. What are some of the cautions and hazards associated with these fuels?
Ethanol is hydrophilic; it loves water. There is frequently a small amount of water residing in the bottom of most gas tanks. This comes from high humidity and/or poor housekeeping. This water is heavier than gasoline, stays on the bottom of the tank and causes few problems. Ethanol, on the other hand, can absorb this water, which can produce service issues.
Because of ethanol's affinity for water better housekeeping is required. Cleaning fuel cans and tanks more often is a necessity. Ethanol has less energy per gallon than gasoline and evaporates more readily. Faster evaporation is helpful in the winter when cold fuel is reluctant to turn to vapor but not desirable in the summer when too rapid evaporation causes vapor lock. Most small engine manufacturers get nervous when there is more than 10% ethanol in the fuel. Concentrations of ethanol above 10% can have a corrosive effect on metals, plastics and soft parts within the fuel system.
What is the bottom line in all this discussion? Ethanol concentrations above 10% can cause problems in small gasoline engines. It you use E10 and a lot of water is present in your tanks and cans, you can end up with a mix that will not run your engine, but will corrode your carburetor and fuel system. Don't attempt to use biodiesel unless you have verified from the engine manufacturer that your engine will run on it. In many states you cannot avoid E10 gasoline. Every station and brand has it. Keep your storage tanks and cans clean and avoid the problems these fuels can support.
— The author does industry training in the Workforce and Community Education Department at Lake City Community College, Lake City, FL. Contact him at
harry_smith@juno.com.
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