What is it? Diesel bug is the common term given to the myriad bacteria, mould and other micro-organisms found in diesel fuel. These organisms live in the water (a result of contamination or condensation) and feed on the intermediate by-products of fuel degradation. Degradation starts roughly twelve weeks after refining.
Marine application of diesel is commonly associated with higher levels of humidity and longer storage of fuel. The trend towards finer filters increases the risk of blockage.
The most rapid growth occurs when the fuel is warm, between 25 – 35 degrees C. In cold conditions, hot return fuel can easily raise fuel temperature to these levels.
Bacteria are prolific producers of bio-surfactants which aid microbial penetration; diesel bug may be noticeable as a cloudy presence. Bio-surfactants may also cause water separators to fail and become a secondary breeding ground for diesel bug. Some bacteria produce copious sticky polymers which cling to glass, entrain rust which would normally settle out and contribute to blocked filters. These polymers are probably the most significant contributing factor to diesel contamination.
What to do? The key is controlling water; significant proliferation of these micro-organisms is not possible without water.
1. Clean your tanks if they are dirty.
2. Keep tanks as full as possible. Turn over fuel regularly where possible.
3. Check tanks for water using a water sensitive paste. Any obvious water should be drained a.s.a.p.
4. Treat the source of the problem.
According to the manufacturers, the surfactant in the Pro-Ma Marine Diesel Treatment breaks down the surface tension of the water. The water blends with the fuel in microscopic droplet size. At that size the water no longer provides an environment for the diesel bug to live in. The water passes harmlessly through the fuel system, the injectors and the combustion cycle before passing out the exhaust as steam.
They also claim that by controlling the water the diesel bug is controlled at the source and it also controls the rust in the fuel system. The detergent in this multi-function product keeps the injectors and fuel lines clean of carbon, varnish and gum formation.
Pro-Ma Marine Diesel Treatment should be used when refuelling as an integral part of regular fuel and engine maintenance. (Treatment ratio is 1:500). Unlike biocides, it is easy to use and is not highly toxic.
Michael Page –Australian Formula 2 Grand Prix Powerboat: “We have found ability to carry less fuel due to decrease in fuel burn, elimination of water contamination in the fuel system…..”
Graeme Balmer, Navigator – Stefan Offshore Powerboat Racing Team “We firmly believe Pro-Ma products have been a key factor in our recent racing success …. Definitely improved performance and reliability in all mechanical areas….”