I've not been on BoaterEd for a while, but figured I would post this to hopefully help out others in the same predicament - I've received a lot of sound advice here over the years.
We lost this summer with the boat in 2 shops for most of it, a large wallet extraction, and without resolution. The local shops tended to throw parts at the problem without a clear understanding of root cause.
Symptoms: Engine will initially start and run just fine when ambient air temps are below 70, but anything above: crank, but no start. Restarts were intermittent as well. We also had issues with vapor-lock in the past, but that is a secondary symptom.
Root cause: Many GM based EFI marine engines (Marine Power, Indmar, Mercruiser, etc.) from the mid to late 90's and beyond had an electric dual-inlet high pressure fuel pump that pressurized the TBI or MPI common-rail type systems. The primary inlet comes from the low-pressure fuel pump and/or directly from the tank and the second inlet is plumbed to the fuel return line to also bring in fuel from that circuit before it returns to the tank via a brass T fitting.
My understanding is that GM and/or OEM's pulled this pump design off the market without providing a direct replacement option. This caused a stall-out with my local shops who did not go the extra mile to do any R&D on a viable solution (they did offer a full repower option however...)
Resolution: Replace the high pressure fuel pump with a single inlet type that matches the fuel delivery specs throughout the RPM range and is J1171 certified. This also requires eliminating the brass T (and come to find out that brass T and the dual-inlet design was a likely contributor to our vapor lock conditions).
I worked with the former owner of American Skier who in turn worked with Marine Power to come up with a viable solution that would meet the specs. We are now back on the water just in time to winterize.
We lost this summer with the boat in 2 shops for most of it, a large wallet extraction, and without resolution. The local shops tended to throw parts at the problem without a clear understanding of root cause.
Symptoms: Engine will initially start and run just fine when ambient air temps are below 70, but anything above: crank, but no start. Restarts were intermittent as well. We also had issues with vapor-lock in the past, but that is a secondary symptom.
Root cause: Many GM based EFI marine engines (Marine Power, Indmar, Mercruiser, etc.) from the mid to late 90's and beyond had an electric dual-inlet high pressure fuel pump that pressurized the TBI or MPI common-rail type systems. The primary inlet comes from the low-pressure fuel pump and/or directly from the tank and the second inlet is plumbed to the fuel return line to also bring in fuel from that circuit before it returns to the tank via a brass T fitting.
My understanding is that GM and/or OEM's pulled this pump design off the market without providing a direct replacement option. This caused a stall-out with my local shops who did not go the extra mile to do any R&D on a viable solution (they did offer a full repower option however...)
Resolution: Replace the high pressure fuel pump with a single inlet type that matches the fuel delivery specs throughout the RPM range and is J1171 certified. This also requires eliminating the brass T (and come to find out that brass T and the dual-inlet design was a likely contributor to our vapor lock conditions).
I worked with the former owner of American Skier who in turn worked with Marine Power to come up with a viable solution that would meet the specs. We are now back on the water just in time to winterize.