Electrical Current Limits for Fuel and Oil Pressure Switches

  After a series of mysterious Westerbeke engine shut downs, it was found that the engine-fuel pressure switch was the problem. Engine manufacturers select pressure switches to safely carry a specific electrical load and adding additional equipment to then is a mistake. Originally this fuel pressure switch powered only the engine indicating instruments and alarm horn. At some point in the engine’s life, the lift pump was replaced with an electric fuel pump that was connected to the injector fuel pressure switch. The engine driven refrigeration control circuit was also added to the switch. This configuration worked for over 100 hours before causing a problem.

Installation of a separate properly sized oil pressure switch would have prevented several dangerous shut downs and a lot of labor hours.

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