Running Rough

[Dave K]

2006 24V with a GM/Marine power. Our boat only has 20 hrs on it so it hasn't been run too much since we bought it August '10.

The engine last fall didn't seem to run consistantly. Almost like it was a fuel delivery problem. Hard to start when hot, sounded like it was missing. The dealer who is servicing the boat had indicated they put some sort of updated kit in the fuel line. I had something to do with engine heat heating up fuel in the line and causing a vapor lock.

I had it briefly running this weekend and it would start well, rpms would go up a bit, ran nice, sounded good and smooth for a few seconds and then it would stall out. When I popped it into gear for a few seconds and gave it throttle the engine would no rev up. Last year when we had a issue of smooth running the service shop said that the fuel pressure "at the rail" ?? was good. I believe fuel filter was changed also.

I know maybe this information might be vegg but I was wanting to ask for some other possible senarios I could ask them to look for. could it be something like timing, bad injector(s), fuel pump?

Also when I started the engine water was dibbling out from somewhere around top half starboard side of engine closer to the back. I took a quick look but with so much stuff in the way I could see where it was coming from. The dealer winterized it and I nowhave a concern of the service not been done right and something has cracked?? Any ideas if there is a hose in the area of the engine that may have been loosened to winterize?

Any info or guesses would be appreciated.

Thanks
Dave.

[whitlock87]

Dave
Does it run fine for about 1 min or so then stall out?
If you run it at low RPM’s will it run fine (below 2k)
Once it acts up, if you shut off the engine and wait it will run fine for short time and then do it again?

If yes to all of the above, check the one wire on the second fuel pump.
This pump is hard to see and you will have to reach under the front of the engine the press the wire on.
I had a isse were my boat would die out as if it was starving for gas. Ran fine at low speeds and would only run over 15mph for a few min. it turned out to be a lose connection on the second fuel pump.
The first fuel pump pulls from the tank to the filter; the second one is a high-pressure pump that feeds the rails.

[Dave K]

Dave
Does it run fine for about 1 min or so then stall out? YES BUT MORE LIKE 5-10 SECONDS

If you run it at low RPM’s will it run fine (below 2k)EVEN WHEN THE BOAT IS IDLING IT WOULD SEEM THERES A MISS. When we are cruising at higher speed it seemed to clear itself up.

Once it acts up, if you shut off the engine and wait it will run fine for short time and then do it again? I HAVE ONLY HAD THE BOAT OUT LESS THAN HALF DOZEN TIMES BUT IT DOES ACT UP MORE SO WHEN IT IS HOT.

If yes to all of the above, check the one wire on the second fuel pump.

This pump is hard to see and you will have to reach under the front of the engine the press the wire on.
I had a isse were my boat would die out as if it was starving for gas. Ran fine at low speeds and would only run over 15mph for a few min. it turned out to be a lose connection on the second fuel pump.
The first fuel pump pulls from the tank to the filter; the second one is a high-pressure pump that feeds the rails.

The dealer who has been doing the warranty and service work told me they did put a new update kit which returns hot gas back into the tank. It didn't really seem to help much thought. Out of the 4 or 5 times I had it out there was one instance where the engine would crank and just turn over and start. When I when to give it throttle it would bog out and stall. Could this be related. Was there a problem with connectors?? I would think if its only wire crimp-on terminals...corosion maybe?? Every time the dealer checked the rail fuel pressure they said it was good, but thats sitting in their yard in a calm enviroment.