The main problem encountered with diesel fuel is contamination from algae--microorganisms of bacteria, fungus and yeast. Individually extremely small (100x smaller in diameter than a human hair), they form colonies that grow into long strings and clumps which can clog fuel lines and filters. Algae survive on the carbon and hydrogen in the fuel and the oxygen in suspended & bottom water. If your tank has significant bottom water, the algae problem will be more severe. The by-products of algae are acid and sludge which contribute to contamination and corrosion in the tank and engine. Biocides can be very effective in killing off algae, however, the dead organisms accumulate in the bottom of the tank. After time or in rough water, the contamination in the bottom can become suspended in the fuel causing plugged filters and motor operation problems.
Where does Contamination Come From?
When diesel leaves the refinery, it is clean, with an acceptable water content. Every stop the fuel makes on its way from the refinery to your boat is an opportunity to pick up algae and water. By the time it reaches your tank, the fuel has become contaminated to some degree. The problem can become worse in your tank if water is present or condensation is allowed to accumulate. The darkness of a fuel tank, especially in warm climates, is the ideal environment for algae growth. Most boaters who are aware of the problem algae can cause, use a biocide which will effectively kill the organisms but will not eliminate the contamination problem. The algae skeletons, along with dirt and rust that may have been trapped in the algae mat, fall to the tank bottom as sludge.
What Problems can Contamination Cause?
Operational problems can occur with only trace amounts of contamination. The most common problem is prematurely plugged fuel filters and plugged water separators. In severe cases, the fuel line can become partially or totally blocked. The microorganisms form deposits on injectors that can lead to inefficient fuel injection and reduced operation economy. These conditions can lead to unanticipated engine stoppage which can be a serious problem especially if your are navigating in tight areas or in bad weather. Corrosion of metal parts is a potentially costly problem that is caused by the acid by-product of algae, hydrogen sulfide. This acid can corrode fuel tanks, injector pumps, injectors and fuel lines and can also attack hoses and tank linings. The problem is particularly severe in fuel tanks where the algae mat traps both moisture and acid against the tank surface. If undetected serious tank damage can result.
How do you Detect the Problem?
A first sign is dark, smoky exhaust that persist even after the engine has warmed up. The accumulation of algae on filters and in fuel lines will eventually cause your engine to starve for fuel. Loss of power at higher RPM is a sign of this. Motor stoppage, especially if it is first encountered in rough seas is a sign of significant bottom sludge which becomes suspended in the fuel in rolling seas and is sucked into the fuel pick up tube. A dark brown or black slime on fuel filters is another sign of severe algae. Any discovery of corrosion in the fuel tank, or other metal parts that contact the fuel should be investigated. A more subtle indicator, one your diesel mechanic may detect, is hard deposits on engine injectors. Normal deposits should wipe clean with a cloth.
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Fuel Polishing Services In San Diego, CA
* Above Photo Shows Contaminated Fuel Lying In The Bottom Of A Marine Diesel
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