I purchased an 02 Centurion knowing it had a "bogging" issue at 3k+ rpms once it was fully warmed up, altough fairly intermittent. Tested the fuel pump out of the water, and a perfect 43 psi. Took it out for a water test today with a fuel pressure gauge hooked to the test port. I ran it for about 30 minutes, back and forth on the water, again a perfect 43 psi. After about 30 mins, it started bogging, and I checked the pressure. When the bogging was about to occur, I noticed a noticble 5 psi tick down in pressure. When it bogged, it dropped all the way to 10 psi. This 100% eliminated any other issues other than the fuel pump.
The mercruiser mag mpi 350 has 2 pumps. One in the fuel cooler (high pressure) and the priming pump (low pressure) at the fuel water seperator. Im guessing the issue is with the high pressure, considering there is no issue at idle or in neutral; only under load and 3k+ rpms. Does anyone know exactly how the 2 fuel pump system works? Am I right here in thinking its the high pressure pump? I have a new one on the way. Has anyone replaced the fuel pump from the genII fuel cool system? I purchased the pump separate from the cooler.