We're just past gas changeover here. "Winter" gas is very susceptible to vapor lock on warm spring days. Many times it's a symptom- or better yet, an advanced warning about other problems. If you have a fuel pump that's not putting out to spec, the vapor lock can expose the problem.

It was darn cold Sunday when he launched,,,, and both motors did it at the same time.

Plus the bat was just put in the water,,, I dont think it got warm enough to do that to both motors,,,, at the same time

Mercury's fix for the 502MPI will cost you an arm and leg. I had the shutting off problem last year. Pretty sure it was from vapor lock. Why else would Merc switched to fuel cool in 98?? I read the bulletin several time tring to pinpoint my problem. I'm sure it's a design flaw. The fuel line from the low pressure pump up to the vavuum tank and high pressure pump, Is steel line that runs along the front of the motors then up and back across the top of the valve cover into steel braided line into the vapor tank. I cut off the steel line about six inches from the low pressure pump and on the other end cut it about four inched past the end of the braided line it now runs out and around the side of the motors and into the vapor tank from the rear using 3/8 fuelinjection line I've run my boat almost 8 hrs this year with no problems.

Hmmm... Was not able to do anything but pull the back seat out and check the fuel tank service port today before work.

There was a few inches of water above the tank... :eek: The electrical wiring that I could see (not sure exactly what it was) was covered in $hit and corroded badly.

I'm going to save the freaking out for later, until I find out exactly what the condition of everything down there is tomorrow after siphoning the water out.

Certainly not thrilled to see the water there though.

I'm not so sure vapor lock is a strong possibility. Having only idled a few minutes at the dock on a decent and all. Usually the engine/fuel has to heat up and causing vapor pockets blocking off fuel supply.

Re-reading the first post it sounds like it had some fuel in th elines enough to start, then once it used it up it died. So it "feels" like fuel starvation.

Just to throw out some simple stuff:

Is there a fuel shutoff somewhere possibly?
Kinked line?
Old maybe clogged fuel separator?
Maybe some gunk on the fuel pickup in the tank? Blow back thru the disconnected line to check for obstruction.
How did the fuel injectors look during the rebuild? Possibly clogged/dirty?

Take some pictures of the carnage

Will do tomorrow. It's ugly.

Hopefully just a clogged drain hole somewhere.

Hmmmm, another puzzle. Why isn't the water around the tank draining into the bilge?

The cover to the tank should be sealed. You should only have the service port not sealed .