Accidental Mixing of Gasoline and Diesel

Accidental Mixing of Gasoline and Diesel

Recently a customer of ours had a problem where their fuel supplier mistakenly unloaded 3000 gallons of ULSD#2 into their unleaded gasoline tank that contained about 700 gallons of gas.

When this happens there is very little that you can do beyond having the tank completely pumped out and then replacing the fuel.

Diesel in gasoline will generally cause the engine to either not start at all of run very poorly.

There is no acceptable amount of diesel in gasoline, although the engine will likely run if the amount of diesel is only 1 or 2% of total.

Gasoline in diesel is an equally serious problem. Even very small amounts (1%) can affect the flash point of the fuel significantly. This lowering of the fuels flash point can have catastrophic effects on the engine as it affects the fuels ignition and can also strip the lubricating ability of the diesel fuel, quickly damaging pumps and injectors.

In the past truck drivers would sometimes add a small amount of gasoline to their diesel fuel to try and prevent gelling. Many of these drivers feel that at long as the engine kept running it must be a good idea. It has never been a good idea for the reasons mentioned above and the fact that the engine kept running does not take into account increased wear and failures that happened days, weeks, or months later.

The addition of Ethanol to most gasoline available today simply makes using any amount of gasoline in diesel a very dangerous proposition.

In general, you should have this contaminated fuel taken away by a company licensed to handle it.

If you ever get gas in your diesel or diesel in your gas, the safest thing is to immediately without running the engine, have the tank drained and then replace with the correct fresh fuel.

Please let us know what you think and any experiences you may have had.

Diesel Doctor

Ethanol/Gasohol Problems with 2 Cycle Engines

Ethanol/Gasohol Problems with 2 Cycle Engines

2 Cycle gasoline engines have new challenges when used with gas containing Ethanol.

A 2 cycle engine gets all of its internal lubrication from a special oil mixed with the gasoline. This premix of oil and gasoline can have serious problems when Ethanol is added to the gasoline. Lubricating oil normally creates a bond with the metal components of the engines. The oil molecules create a boundary layer that protects the metal and reduces friction.

When Ethanol is present it will actually get between the oil and the metal, preventing the boundary layer from forming. This results in little or no protection for the moving components, and little or no reduction in friction forcing the engine to work harder, run hotter, and often to destroy itself.

Also many small engines have plastic carburetors, fuel tanks, and other components that Ethanol can soften or dry out which will cause them to fail. Many rubber fuel lines, o-rings, gaskets, and other parts can be delaminated or turned to a gelatin like material often failing very quickly.

Storing this type of equipment with Gasohol (Ethanol blended fuel) can lead to catastrophic failure in a relatively short time.

There are a very small number of additives that can reduce the negative characteristics of Ethanol in the gas.

We recommend that everyone operating 2 cycle engines switch to a pure synthetic two cycle oil.
The synthetic oil will provide the boundary layer lubrication in spite of the Ethanol.

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