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Using Car Diesel in a Marine Engine

I decided to pump the diesel fuel out of the bottom of my tank and see what kind of crud shows up. If it is bad, I will pump the whole tank, but there is no diesel fuel sold at my winter haul-out place. Nearest pump is four boating hours south. My question is, can I put in 10-gal Car Diesel fuel till I get down river and fill up at the boat yard? Is it the same stuff but with the marine color agent? Don't contact the Diesel Police, please! Capt Al, Kindred Spirit #55



  • The only difference in the fuels are the color additive and road use tax. The color is to let the "Diesel Police" (DMV) know if you are using non-tax paid fuel on the highways. In North Carolina, we have a 42.5 cent per gallon road use tax. There is no reason you should not use the fuel in your boat. There is a hefty fine for going the other way (red diesel means no road taxes were paid).

  • Actually you are better off buying your diesel at a truck stop, it is probably cleaner fuel. A trick to drain the tank: disconnect the fuel line at the tank and replace it with about 20 feet of cheap 1/4 inch plastic tubing, then pull your speedometer paddlewheel and drop the tubing through the hole. You can siphon the fuel from outside the boat, no mess or smell in the cabin.

  • Go to your local truck stop and get some of whatever they're selling. Usually, in the winter they sell #1 diesel or a blend of #1 & #2 cause it's thinner and won't get goopy in cold weather. Summer time they usually sell #2 diesel. Stove oil used for heating is usually #1 diesel - with no use tax :).