Marine

---

Diesel fuel can easily become contaminated with microorganisms such as bacteria, mold, fungi, and algae.  Water in diesel will culture a microorganism or bacteria that feeds on the hydrocarbons in the fuel, therefore degrading the fuel. Water is the worst form of diesel contamination. Good fuel is clear and bright.  Fuel that has turned dark, almost black, is in a far advanced state of degradation. This darkening is accompanied by a form of contamination that clogs filters and causes poor combustion.

Diesel engines only use a small percentage of the fuel entering the system.  This allows warm diesel to return to the tank which encourages condensation and provides a ripe environment for microbial contamination.

Biocides may be added to the fuel to kill microbial activity, but this only causes solids and debris to settle to the bottom of the tank forming a thick sludge.

Fuel circulates and clogs filters causing a mechanical shut-down due to fuel starvation. Continual filter changes address the symptom, but do nothing to correct the problem.

Contaminated fuel should be replaced with fresh fuel or polished to a clean dry state. Removing contaminants from your diesel fuel can extend the lifespan of your equipment and reduce maintenance costs. 

• Fuel over 1 year old
• Loss of power or RPM's
• Excessive smoke
• Transom soot
• Clogged filters
• Dark or hazy fuel
• Particles or algae visible in the water separator bowl

In general, diesel fuel should only need to be polished when contamination and symptoms are evident. Small amounts of water can easily be removed from your on-board fuel/water separator - remember to check the bowl frequently. Especially after taking on a load of fuel as water can enter anywhere along the distribution line. Poor or minimal maintenance at fuel stations can allow substantial amounts of water to enter the tanks.

Remember, it only takes a few ounces of water to fill the bowl of the fuel/water separator and if the separator does its job, water reaching the check valve will stop the flow of fuel and cause a mechanical shutdown.

Recently, we had a vessel take on a load of fuel in the Bahamas. Unfortunately, the storage tank was old and had allowed ground water to seep into the tank. Shortly after refueling, the boat suffered a mechanical problem. The fuel/water separators were old and had not been rebuilt. As a result, the water passed through the check valve and entered the fuel lines causing two injectors to break; an expensive repair away from home port.

Samples should be drawn from the bottom of each diesel fuel tank as this is where sludge, water and particulate matter will settle.  This sample will provide a visual inspection of the fuel and will indicate any obvious problems. 

If contamination is evident, on board testing can pinpoint the problem.

Onsite Diesel Tests

Our tests asses five critical areas, they are:

Clarity

• Evidence of sludge, mold, bacteria and other contaminants

Water

• Free standing water accumulates on the bottom until stirred up

Suspended Moisture

• Fuel appears hazy

Mold

• Active growth

Bacteria

• Active growth

If significant free standing water is evident an additional test can be done to identify the depth/volume at the bottom of the tank.

Actual mold and/or bacteria growth must be addressed immediately. A quality biocide should be used to kill the microbial growth. Frequently the growth is so pervasive that strands of the bacteria can be seen growing in the glass bowl of your fuel/water separator as well as mold attaching itself to the sides and top of your tanks.

An in-depth lab analysis can be done to identify cetane index, unidentifiable particulate or sludge contamination, acid number, flash point, or extended storage ability.

Diamond Diesel uses the patented polishing systems, which together with our vacuum and pressure cleaning system removes all water from the tank and moisture from the fuel. At the same time sludge and particulate matter is removed to below 1 micron, resulting in water free, clean, dry fuel.