Mercruiser 454 MPI fuel pump questions
Guys, was trying to help a buddy with his boat this afternoon. Just want a reality check.
He has a pair of ~2001 Mercruiser 454 EFI/MPI engines.
One engine quit on him a while back and he's just now gotten around to fixing. He had some electrical issues, and somewhere along the way his starter went bad. They replaced the starter, and now the engine cranks fine, gets spark, but won't run.
I noticed that the "good" engine, as soon as you turn the key on, the fuel pump loudly runs for about 2 seconds - just like most cars. On the "bad" engine, no such luck. I swapped what I believe were the fuel pump relays between the two engines, with no change in behavior. I could not find a fuse or anything like that, but did find a 50A circuit breaker on the top of the engine that was fine.
It was getting dark and a little cramped but I'm pretty sure I unplugged the fuel pump from the harness and verified that 12v was getting to the harness. So I am assuming the pump is shot. This is a little surprising because he just had it replaced it a few months ago.
- Is there anything that would stop the fuel pump from pressurizing the system at key on? IE any pressure switches to check, etc?
- The pump itself seems to be in some sort of weird assembly that cooling water runs through? I guess it's a heat exchanger? Is this a single unit or can the electric pump alone be replaced? I was too contorted to really get a look at it... how tough a job will this be?
- Is this that common a failure?