High Fuel Pressure 2008 MerCruiser 350 Horizon MPI

[kib1702]

Hi again! Changed both complete fuel modules. Still have both engines stall after running for 15-20 min. Checked pressure on both rails and it drops to 0.

Both fuel pump connectors get hot.

Checked all grounds and they are OK.

After waiting for about 25-30 min or after unplugging main harness connectors both engines start. When i unplug the main harness connector there is clicking in sender unit on gas tank.

Also checked the AMP draw and its 17 amp at the both fuel pump fuses.

Can all of this be because of restricted flow on fuel flow meter(scanner) on gas tank sender unit? Does any body have a wiring diagram for my engines?

 

[alldodge]

One engine dies without warning, fuel pressure at 20-23psi. Replace parts then both have pressure at 80 to 100 psi. Replace regulators on fuel module and rail on both engines, now port still dies. Later starboard engine dies,

Is this a hurricane boat, had salt water in the harness and boat?

 

[kib1702]

One engine dies without warning, fuel pressure at 20-23psi. Replace parts then both have pressure at 80 to 100 psi. Replace regulators on fuel module and rail on both engines, now port still dies. Later starboard engine dies,

Is this a hurricane boat, had salt water in the harness and boat?

No, this boat newer had water in it.

 

[alldodge]

No, this boat newer had water in it.

OK, that starts to help a bunch. The boat had water in it, and if it was salt water it makes it even worst. How far up did the water get?

 

[kib1702]

OK, that starts to help a bunch. The boat had water in it, and if it was salt water it makes it even worst. How far up did the water get?

Sorry, but this boat NEVER had water in it...........................
Sorry again i misspelled it.

 

[alldodge]

Things just don't add up, I'm at a loss of how both engines can suffer from the same thing at the exact same time. You sure you have good clean gas in the tank and filters have been changed?

Your post 6 stated boat would go to 4500 rpm at 27 knots, while the MPI Horizon motor is spec at 4800-5000 this rpm is within the area prop pitch change. Was the engine ever able to reach the 4800 plus rpm?

 

[kib1702]

Things just don't add up, I'm at a loss of how both engines can suffer from the same thing at the exact same time. You sure you have good clean gas in the tank and filters have been changed?

Your post 6 stated boat would go to 4500 rpm at 27 knots, while the MPI Horizon motor is spec at 4800-5000 this rpm is within the area prop pitch change. Was the engine ever able to reach the 4800 plus rpm?

Yes it did go up to 5000 RPM and it did about 30-32 knots in the past.

It got damaged in hurricane Sandy, only hull.

It was on land for two years. End of the last summer i put it in the water and it was running fine.

Properly stored it for winter.

All problems started this summer.

The fuel in it is new. It was almost empty and i got it filled in very begining of this season.
All filters are new.

 

[Fun Times]

Being you have a Sea Ray boat, you'll want to check to see if your boat has a Parker / Skinner solenoid valve located around the fuel tank area. Should something fail it could restrict fuel. Some Sea Rays have them while some don't from my understanding. Here is a good topic covering the valve with photos for you, http://clubsearay.com/showthread.ph...l-Solenoid-Manual-Overide?p=265352#post265352

 

[kib1702]

Being you have a Sea Ray boat, you'll want to check to see if your boat has a Parker / Skinner solenoid valve located around the fuel tank area. Should something fail it could restrict fuel. Some Sea Rays have them while some don't from my understanding. Here is a good topic covering the valve with photos for you, http://clubsearay.com/showthread.ph...l-Solenoid-Manual-Overide?p=265352#post265352

Do you know what will trigger this solenoids to close the flow?

 

[alldodge]

Had one similar (different manufacture) used on my generator. When 12V is applied it opens, when voltage is removed it closes. The good is if working properly no fuel will leak or drain in to anything once power is removed. The bad is you have 3.8 fuel line feeding them, the fittings used chokes the line down to 1/4 inch. If there is any build up on the valve it can choke the fuel supply down further.

The screw on the front of it is a manual over ride, you just turn the slot so that it is inline with the fuel lines. Most don't use them anymore, they just use the anti-siphon valve on the tank which connects to the line

 

[kib1702]

Finally i got it fixed!!!
Had to eliminate the connectors on power wires to fuel pumps and solenoids. The wires are not hot anymore and AMP draw is down to normal.

What was really weird is that i checked and cleaned all connectors before, but they were getting hot and were triggering the computer to shut down the fuel shut-off solenoids.
Took the boat out so far everything is ok.

I appreciate the help.
Thank you very much!!!!!!!!!!!!!!!!............................