Will gasoline harm my diesel engine?

[D. Young]

Gasoline was mistakenly pumped into my boat by a dock attendant while I took care of some business in the marina office. The mistake was not found until black smoke boiled from the exhaust. The engine (Yannmar 2qm15) was subsequently pumped out, and freshly re-filled with diesel. Engine seems to be running o.k. with the exception of an occasional puff of black smoke every few hrs. I also changed all filters. Did I get lucky? or should I expect problems?

 

[Curtis Collins]

Absolutely gas can damage a diesel engine. Gas is more refined than diesel and thus has less lubricating qualities and is a much more volatile fuel than diesel. If you bled all the gas from the system and changed filters you may have gotten lucky, but I would have a good diesel guy check it out just to be sure.Curtis

 

[Patrick Ewing]

This happened to a car of mine once

and it was ok. The top speed increased by ten mph for a few thousand miles though. I noticed no other problems. If I were you, I would change the oil and all oil and fuel filters, then run it for a few hours at the dock. Then change the oil again and hope for the best. You might want to join Vessel Assist or get towing insurance. Good luck.

 

[Jim Logan]

You might be lucky

Gasoline in a diesel engine has several very bad effects. 1. The lubricity of diesel is much higher than gasoline, which means that running a diesel on gasoline is very bad for the precision fit of the injection pump and will quickly ruin it. 2. You probably didn't have enough gasoline in your engine and tank to matter after the pumpout, since a diesel engine with significant gasoline in it will tend to "run away" or have serious knocking in the cylinders since the lower flash point of of gasoline causes predetonation on compression. In sum, gasoline doesn't do anything good for your diesel, and I would do anything I could to get the gasoline out of the fresh diesel, including pumping out the tank again and refilling with fresh diesel again, if symptoms are still being seen. The fuel dock guys should not have made this sort of mistake.

 

[R. Palaia]

I have heard this happen many times to people

I have heard about gas in diesel, diesel in the water tanks, etc, etc, etc. So what I always do, even when I go to my local fuel dock and the manager hands me the hose, I always say "this is diesel, right?" And he says "yup". I do this even if I say I need diesel as I'm motoring up to the dock. They might still go for the gas hose out of habit.Roc

 

[Victor Robert]

What is in this hose ?

Instead of the leading question "This is diesel, right ?" a better question to ask at the fuel dock is "What is in this hose ?". This forces the dock attendant to think and create the answer. The universal response to a question you did not fully understand in your second or third language is to smile and nod politely. I caught myself doing it once in Germany.Also, my boat came with a red fuel cap. I quickly changed it to a green one and believe this may have saved me on at least one occasion.