7.4 mpi wont turn wide open

[sammi]

My friend has a 1999 34 sea ray. The starboard engine will turn wide open fine but the port engine will run great up til 3100 rpm. If you push it past that it will bog down and just won't go higher. Removed air filter so its not that and water separator was changed and it was clean with no water. Any ideas?

 

[bondo]

Ayuh,.... Bein' an MPI, ya pretty much need a diagnostic computer to find out what's wrong, aside from verifin' that all the hard parts are workin' right, distributor cap, rotor, fuel filter, etc...

 

[Docksidemarineservices]

Actually going to need a fuel pressure gauge, a compression gauge and a leak down tester.

 

[sammi]

Does anyone know if there is a fuel filter besides the water separator?

 

[sammi]

Mechanic came down. No codes but losing fuel pressure above 3000 rpm. Does it matter how the low pressure pump by the tank is oriented? One appears to be upside down, of course its the one that looks upside down that is running good. How do narrow it down between the regulator, low pressure pump or injector pump?