2008 Mercruiser 4.3L MPI fuel pump problem

[stucz_cro]

Hello everyone!
I'm having this problem with my new Mercruiser 4.3l MPI. Engine is just 2 years old, all inspections have been done and I really take care of it.

Well, 3 weeks ago, while cruising engine just turned off. When I tried to start it again i didn't hear fuel pump sound, and engine just wouldn't start. I took it to mechanic and they replaced fuel pump, but one week later same situation. I checked all fuses and nothing appears to be wrong. I took the boat to mechanic again and he said that he tried starting the engine every day for the last 10 days and that fuel pump works just fine and that engine starts normally.

Do you know what else could we check? Could it be bad fuel quality? Any idea?

I would be very grateful if someone could help me, since mercruiser mechanic (in croatia) doesn't know what to do next.. :-(

Thank you very much,

Nikola

 

[stucz_cro]

bump

 

[TurboK9]

Re: 2008 Mercruiser 4.3L MPI fuel pump problem

Either have the mechanic try this, or do it yourself. Bring a test light or voltmeter with you and drive the boat around until it dies again, or run the boat on muffs or dockside and see if it dies again. If it does, and won't restart, check for current AT THE FUEL PUMP. If there is no current at the pump, then you likely have a faulty oil pressure sensor cutoff switch. This is inline with your fuel pump and if faulty can cut the circuit to the fuel pump for several hours or more. It could also be something loose in the same circuit that jostles when under way, and breaks the circuit to the pump.

EDIT:

If you are going to try this on the water, bring along a piece of wire w/ clips to use as a jumper. If the cutoff switch is the problem, you can jump it to close the circuit at the switch itself, and get back to shore. This, of course, assumes the problem is not low oil pressure, LOL. The switch should be port side, near the bottom of the engine. Also, if you do this and she fires up, thats proof positive that the switch needs replacing.

Good luck!

 

[stucz_cro]

Thank you very much! Will try this as soon as possible!

Nikola

 

[Don S]

Re: 2008 Mercruiser 4.3L MPI fuel pump problem

You have an MPI engine, there is no oil pressure switch that controls the fuel pump. That is on carbed engines only. IF the fuel pump system is anything like earlier models, the fuel pump is controled by a relay which is controlled by the ECM. These all go through several fuses and harness connections that could be loose or corroded causing an intermittant problem.

 

[stucz_cro]

Re: 2008 Mercruiser 4.3L MPI fuel pump problem

Thnx for reply!
Summer is getting closer and i still haven't solved my problem! I've spent ages looking for mechanic who could repair that, but no use! Now I'm back on the begining, but this time with one more problem!

5 months after winterization I'm trying to start the engine. All devices on board are working (lights, radio, horn...) but engine is dead. When i turn ignition key nothing happens; no beep, no fuel pump sound - nothing. Before winterization guys at service center said that everything worked fine - no problems at all...
Any ideas?

Thnx a lot

 

[stucz_cro]

Re: 2008 Mercruiser 4.3L MPI fuel pump problem

Solved!
110A fuse placed somewhere on starter was "broke"

Still don't know if the problem with sudden shut down remains, or could that broken fuse be the problem...

Thnx anyway