Good morning, I dove into these...

[Phat]

Good morning, 

I dove into these threads and found what I thought was a fix on my port engine, apparently it wasn't.  2001 SB 400 with a pair of Cat 3126s.  The port engine would turn over but not start, so in looking around I noticed people were saying to replay the Fuel Relay, Cat 115-1516.  Well I did and it cranked up immediately!  So tried to crank up 2 days later and same problem, it just turns over.  Replaced the relay with a new backup and no change, just keeps turning over.  I did notice the this relays control voltage would come up from 11V to 13V after about 20 seconds. Is there another fuel solenoid that could be a problem?

[wingless]

Welcome to the forum.

This image shows the Parker Skinner hull fuel solenoid valves on my 2000 380DA w/ Mercruiser 454 engines.

The twist knobs change the function from Automatic (controlled by engine fuel pump power) to always on.

The Sea Ray factory uses a custom tee electrical wiring harness to branch off the Mercruiser fuel pump powering to control this hull fuel solenoid.

https://live.staticflickr.com/65535/48901381777_a53823f14b_c.jpg

The fuel system on your boat may be similar.

[Phat]

Thank you wingless, I'll take a look.

[Captain_Mark]

I have owned my 3126's for 14 years and have replaced the 12v relay that serves the fuel solenoid. One in each engine electrical box. The BWD brand #R3112 is what I have installed now for 10+ years without a problem. With my E.R. hatch open I can hear the fuel solenoids snap back into the open position by moving my helm switch to the "on" position. If no snap, than no run....
Diesels are a simple beast, they need air, fuel and you not to exceed rated temps for that engine.