A diesel’s fuel system produces more problems than any other part of the engine. Regular fuel system inspection and maintenance will keep your fuel clean and your engine running reliably.
Even a small amount of dirt or water in a diesel’s fuel system can seize or corrode the injectors or injection pump. For this reason, marine diesel engines have both primary and secondary fuel filter systems.
Inspect your primary filter’s sediment bowl daily and drain any sediment and water. If the sediment bowl fills and requires draining more than once every 100 hours, the fuel tank is contaminated and must be cleaned. Replace the primary fuel filter element at the first sign of discoloration.
Secondary fuel filters stop the contaminants that escape the primary filter. Although they stay clean longer, secondary filters should be replaced with every other primary filter change.
If the engine isn’t getting fuel, either the supply or injection pump is broken or the injectors are clogged. Air trapped in the fuel system prevents fuel from flowing and must be bled out.
Diesel fuel stored for a long time without being treated can grow bacteria that can clog the fuel-filtering system and cause the engine to lose power. If this happens, clean or change the filters and bleed the system to eliminate air.
For more information about maintaining your marine engine(s), take the Engine Maintenance course at a squadron near you.