Had an interesting one at the lake this last weekend. Boat started great on the trailer, and then again in the water at the launch. Idled out into the no wake zone and then it coughed, died, and would not restart

. Managed to get it turned back towards the docks and tied up while trying to crank and start.
Definitely fuel related. It would crank, cough, die, crank run for 3-4 seconds and then die. This pattern repeated for about an hour with wait time in between to cool the starter and let out a string of profanities.
Finally as the batteries were dying and I was throwing in the towel, the damn thing started and idled great!

Tied it to the dock and just watched it idle it's merry little head off for a few minutes and then decided to brave the no wake zone. We purred on out the no wake, got past the buoys, hit the gas and had a great rest of the day.
Fuel pressure the entire time was 5.5 - 6.5 on the gauge although it's not liquid filled and does shake a bit.
Good news is the water temp is better with the new plumbing. 130-140 under way and max 180 at idle.
Also made friends with a couple of the sheriffs. They were pretty cool when we tied up to their dock, the closest one after the stall in the no wake. We had some banter back and forth both at the dock and on the water after we got up and running; they were glad we were able to salvage the day.