Can you give a little more detail about stop running? Does it sputter out? Suddenly die with no warning?

 

Yes, with no warning the engine will just die, Or, with no warning the engine will skip and then return to the previous RPM's. No alarms or no codes show up on the Smart Craft system, or the DIACOM software.

 

Double check all grounds. Check oil pressure sensor connection. And drive lube monitor connections. I believe this are the only 2 things that will kill the motor when running. If you have the Diacom, can you or someone else drive and watch that engine when this happens. If lucky a screen shot

 

Scott
I changed the oil pressure sensor. Let the engine run for about 10 minutes at 1700 rpm's. I did notice the fuel pressure drop twice from 48 psi to 33psi. But the engine did not cut off during the 10 minutes. I'll take the boat out later today and let you know how it goes.
Thank you for your help.
Mark

 

I think your looking for a new fuel pump. Shouldn't drop like that

 

So that was not under a load

 

Correct, not under load

 

I had a similar issue on a 260, You can find my previous thread and see what all happened and I did. It wound up being one of the fuel pumps in the cool fuel module going bad. I'm not sure which one since I replaced both. No issues afterwards.

 

Thank you
Mafk

 

You're welcome. When the motor shuts off, you should still have fuel pressure on the gauge. If it shuts off and shows 0 pressure, then it's a fueling issue. Whether it's a fuel pump dying and not pumping fuel or an extreme blockage and no fuel can get through the lines or an electrical issue and losing power to the fuel pump for some reason.

Another fueling issue I ran into in the past was, one of the wires inside the cool fuel module, on the pumps, power wire was not making complete contact. Secured the wire and all was good again. But this was a no start/no fuel issue.

 

Thank you for your help.
I ordered a new Cool Fuel module.
I'll make sure the lines are clear when I install it.
I will let you know how it does.
Thanks again.
Mark

 

You're welcome. Also if you want, you can just replace the pumps instead of the whole module, save a little bit money but that is completely up to you.

 

So I installed the new cool fuel module today.
Ran the engine at 2200 rpm’s for 30 minutes at the dock. Ran like it was brand new. Didn’t skip a beat. Fuel pressure was where it should be. We have a big Nor’easter today, so I can’t take the boat out for a test run under load today. I’ll do that when it calms down some.
Thank all of you for the help.
I really appreciate it.
Mark

 

Awesome, glad it worked out .

 

This morning, I took the boat out for a test run and the starboard engine did the same thing of just stopping.
I am running out of ideas.
Does anyone know what the Shrader type electrical valve mounted on the fuel tank does.? There is a knurled screw with a screwdriver slot mounted on the fuel tank. Which direction should the slot be pointed? I was thinking if the slot is vertical, it would cut off the fuel? If the slot is horizontal, it would be open. After the engine cools off, I am going to take the fuel lines off from the input to the Cool Fuel Module to the output of the tank. See if there is an obstruction?
Thank you for any help.
Mark

 

That is a fuel shut off solenoid. If you look at the valve where the slotted screw is, it should say "norm" and "bypass". In "norm" mode it operates as it should for whatever safety reason. In "bypass" mode, it just bypasses whatever the safety feature it is and just flows fuel.

You can turn the slotted screw to "bypass" and see if the motor still continues to die. I'm sure there is an actual way of testing the solenoid but I'm not exactly sure how. You could also swap the solenoids from port to starboard and see if the problem follows.

If you swap solenoids or just turn the current one to bypass and the problem is gone, that could be your problem.

 

Thank you.
I'll try that tomorrow.
Thanks again.
Mark

 

I took all the fuel lines off and made sure there were no obstructions.
One thing I was surprised about was there is no pickup line/pipe running into the tank from the brass 90 degree elbow on top of the tank. I had just assumed there would be some sort of line running into the tank down into the gasoline.
My tank is about 1/2 full of gasoline. Took the solenoid off and blew through it. I set the Parker solenoid to bypass.
So, I will try it again tomorrow if the wind will ever die down.
Thanks for your help.
Mark

 

Sounds good, let us know what happens.

Also, have you checked wiring and connectors from fuel pump relay on top of the motor to the cool fuel module? Look for any breaks or kinks in wires. Look for any burning at the connectors.

 

Interesting thing about the fuel pressure. Even after engine stop, the fuel pressure should remain in the fuel rail for quite some time, rather than immediately go to zero. My money's (well actually your money) on a bad fuel pump.

 

We

 

I think my problem has been solved. The connector at the top of the photo below was so hot you could not touch it. ( Not the power to the cool fuel mod) When i wiggled it the fuel pressure went to zero and the engine cut off. I was able to repeat this several times. When I unplugged the connector the plastic around one of the metal connectors was melted. I cleaned both connectors and closed the female connector. Put it all back together and took the boat out for a spin. The engine didn’t cut off and the fuel pressure stayed constant . Checked the connector to see if it was hot. It was not. Ordered a new connector and will install it tomorrow.
Thank you for all your help. You have been a great resource.
Thanks again
Mark

 

That's great, I'm glad you were able to find and figure that out. That's why I mentioned checking all wires and connectors as well because I had the same thing happen before, but at the cool fuel module plug. Spliced new connector in and never had a problem again.

Do you know why or how it became melted? Was it resting on the exhaust manifold? If not, then I would figure out what the connector is for and why it may have burnt up.

 

@MDavidson . What connector is that. Is always good to learn new places to check for issues

 

Don't know what the connector does. Doth ends go into a wiring harness. The wires are numbered 1000, and 1001. Been searching for a wiring diagram with wire numbers. As of today, I have not been able to find a wiring diagram with numbers. Still looking. Still don't know why the connector melted inside.
Trying to figure that out.
Thanks again for all your help.
Mark