I have a 1994 Supra Sunsport with a 5.8 Pro Boss. I am having terrible starting issues. Upon launch, boat starts but is very hard to start. After it starts it will run fine. After it shuts down and upon attempting to start, it fires quickly then dies. It takes up to 5 minutes to get it restarted. Pulling off the flame arrestor, you can't see any gas coming out of the throttle body injectors. After a while, sometimes having to tap around the high pressure pump, fuel starts to squirt out of the injector and the boat will start.

We have replaced both fuel pumps and the fuel filter along with the fuel pump relay. Mechanics are perplexed. any help will be greatly appreciated.