“Give a diesel engine clean fuel and it will run forever.”
This old saw is less of an exaggeration than you might think. Don Casey with Boat U.S. states “Repair statistics show that 90% of diesel engine problems stem from contaminated fuel. This should put fuel-system maintenance at the top of your list.”
If the fuel is efficiently filtered on the way to the nozzle you should not have to worry about contaminated fuel while fueling up. If you have any doubts about the cleanliness of the fuel, pump some into a clean glass jar and let it sit a few minutes. Water and dirt will settle to the bottom. If you see either, filter the fuel before it goes into the tank, or better yet, buy your fuel somewhere else.
It is easy to claim you were sold bad fuel, but chances are the contamination is happening inside your fuel tank, not the suppliers.
Here at Semiahmoo Marina, we take extra precautions to ensure the quality of fuel sold to our customers. Read more at Semiahmoomarina.com
Water is the most damaging contaminant found in diesel fuel, and it is the primary cause of additional fuel breakdown. Water can come from humid air, condensation on the wall of a fuel tank or be mixed in with the fuel when it is purchased at a marina. The basic rule when it comes to water in diesel fuel, if it is present, remove it. If not, microbial growth and possible tank damage will occur.
In an article at Marinalife.com, Reliable Diesel Fuel Matters, written by Capt. Jeff Werner, it is recommended to develop a three-part fuel preventive maintenance program: sampling, testing, and polishing. As with all preventive maintenance programs, a small amount of time used up front will stop problems and costly repairs from developing in the future. Maintaining your yacht’s fuel supply is just an inexpensive insurance policy for the fuel system and engines.
Sampling – Samples should be drawn from two locations within the tank: the bottom and center. Since water and other debris will settle to the bottom of a tank, it is important to detect and correct for those contaminants. A mid-fuel level sample will test the overall fuel quality. Samples can be taken using a specially manufactured, inexpensive hand pump that collects the fuel in a plastic bottle.
Testing – Once the samples are collected, they are sent to a fuel testing laboratory for analysis.
Polishing – Kevin from Petro-Clean quotes “As tank cleaners, we “polish” the fuel (pass it through a tight-weave water-absorbing filter) when we service tanks, but it is the cleaning of the tank that really makes the difference. Polishing can remove debris and water that is in suspension, but the majority will still be sitting on the bottom of the tank, just as described with the glass jar.
We like to think we have some parallels with dentistry- cleaning teeth and cleaning tanks are both easy to put off, but both are essential maintenance. If you go too long, the scum can build up on the floor of a tank like plaque on teeth, and without regular (3-7 yrs.) cleaning, cavities can easily develop. Cavities in teeth can be filled and corrosion in tanks can be patched and repairing what you’ve got is often better than replacing it all (certainly with teeth!)
We also wear blue gloves like the dentist =) “