18. Fuel pump pressure

We are told by engineers from Zenith that the needle and seat of the float valve assembly is designed to satisfactorily regulate the level in the float chamber up to 4 PSI. We know from our own experience that fuel pump pressures in the range of 2 PSI can cause the engine to lose power. For this reason, we recommend a nominal fuel pump pressure of 3 PSI for most boats.

If you have any reason to believe that you have more than normal head loss in the fuel line from the tank to the fuel pump, we recommend a 4 PSI pump. Most mechanical pumps in good condition appear to produce 3 to 4 PSI. In the case of FACET (electric) pumps, the 3 PSI pump is model number 477-060, and the 4 PSI model number 476-087. - Updated: November 4, 2003