Hey guys, really stumped on this one. Originally posted on THT but haven't gotten much help:
Update 1:
The motor in question died while idling out to go fishing last November. Since, it has failed to sputter or restart at all. We have bypassed the kill switch with no change except an audible alarm, charged his batteries which are older and were depleted a bit (around 11.9-12 volts), and tested for spark on all cylinders (there was spark on every cylinder).
A few years back, we replaced both of his lift pumps that fill the VST tank and cleaned the VST tank and replaced the filter in there. The primer bulb stayed firm during all of this so we are guessing it isn't the lift pumps but we will test.
Update 2:
We spark tested it...it has spark on every cylinder, albeit it seems weak.
Update 3:
Hey guys, just an update: the owner bought a new boat and I bought this one for a pittance. It still won't start. Here is why has been tried:
1. VST tank is filled at least half-way with fuel (hard to tell as some spills when opening the tank). The lift pumps seem to be working as the primer bulb is holding a prime. When I tested the fuel line from the lift pumps into the VST for fuel while cranking, a small amount of fuel was being pumped from the lift pumps.
2. The VST fuel pump has power and cycles on. No fuel pressure was detected at the shraeder valve. I replaced the pump with a new one from Quantum Fuel Systems, a company I've had good experiences with. I now have erratic/intermittent fuel pressure up to 45-50 psi when turning the key and the new pump runs/whines. It seems fuel pressure drops to zero when cranking and the test light goes weak.
3. I am unsure how to test the main relays or ECU, besides attempting to apply 12 volts of power to the large terminals on the former. At $30 a pop, I may just replace the relays which from the diagram, control fuel pump operations and the ECU/injectors. I am unsure how to test the high pressure fuel pump but believe it may be the culprit as it has not, to my knowledge, been addressed. I do not have access to YDS software.
Update 4:
Tried cranking with a test light wired to the fuel pump terminal (VST)...bright light with key on that goes dim while cranking but stays lit. Brand new 1000 MCA battery. Brand new VST fuel pump whines a bit with the key in the on position so I know it's running. VST tank is about 2/3 full of fuel.
Update 1:
The motor in question died while idling out to go fishing last November. Since, it has failed to sputter or restart at all. We have bypassed the kill switch with no change except an audible alarm, charged his batteries which are older and were depleted a bit (around 11.9-12 volts), and tested for spark on all cylinders (there was spark on every cylinder).
A few years back, we replaced both of his lift pumps that fill the VST tank and cleaned the VST tank and replaced the filter in there. The primer bulb stayed firm during all of this so we are guessing it isn't the lift pumps but we will test.
Update 2:
We spark tested it...it has spark on every cylinder, albeit it seems weak.
Update 3:
Hey guys, just an update: the owner bought a new boat and I bought this one for a pittance. It still won't start. Here is why has been tried:
1. VST tank is filled at least half-way with fuel (hard to tell as some spills when opening the tank). The lift pumps seem to be working as the primer bulb is holding a prime. When I tested the fuel line from the lift pumps into the VST for fuel while cranking, a small amount of fuel was being pumped from the lift pumps.
2. The VST fuel pump has power and cycles on. No fuel pressure was detected at the shraeder valve. I replaced the pump with a new one from Quantum Fuel Systems, a company I've had good experiences with. I now have erratic/intermittent fuel pressure up to 45-50 psi when turning the key and the new pump runs/whines. It seems fuel pressure drops to zero when cranking and the test light goes weak.
3. I am unsure how to test the main relays or ECU, besides attempting to apply 12 volts of power to the large terminals on the former. At $30 a pop, I may just replace the relays which from the diagram, control fuel pump operations and the ECU/injectors. I am unsure how to test the high pressure fuel pump but believe it may be the culprit as it has not, to my knowledge, been addressed. I do not have access to YDS software.
Update 4:
Tried cranking with a test light wired to the fuel pump terminal (VST)...bright light with key on that goes dim while cranking but stays lit. Brand new 1000 MCA battery. Brand new VST fuel pump whines a bit with the key in the on position so I know it's running. VST tank is about 2/3 full of fuel.
