Ron Schuler, UW Extension Ag Engineer, recently reported that bacteria and fungus “infections” are possible in diesel fuel and can cause clogged fuel filters and fuel injection nozzles.  This problem is most likely to occur when water accumulates in the fuel system, primarily the fuel tank.  Also, it is more prevalent when an engine is not used for long periods of time. These microorganisms are able to live in the water and feed off the fuel.   

        The first sign of a problem is an accumulation of a mucous like layer on the fuel filter element /medium. Draining the fuel system will reduce but not eliminate the problem.  There are biocides available to destroy the microorganisms in the fuel system.  Power Service Product (Address P.O.Box 1089, Weatherford, TX 76086, 1-800-643-9089, psp@ powerservice.com) has a biocide called BioKleen for this problem.  Another product is Pri-Ocide, sold by Power Research Inc. (6970 Portwest Drive Suite 180, Houston, TX 77024, 1-713-490-1100, pri@priproducts.com).

        To reduce the risk of a microbial diesel fuel infection, drain the water trap in the fuel system frequently.  When changing the fuel filters, look for the mucous like accumulation.  If the mucous is present, use a bio-cide. Check with local fuel supplier as a potential source of the bio-cide.  

        Take steps to reduce the potential of water from getting into the fuels.  Be sure fuel tank caps and/or covers are in place unless the tank is being filled or serviced.   Fill the tractor fuel tank at the end of each day instead of in the morning, which reduces the potential for water condensation in the tank.