After 12 hour fishing trip where it ran perfect till the end when it idled too low. Another short trip was fine, but had to manually advance the idle to 700 rpm to match the SB engine. Last two startups it died at idle and when I gave it more throttle it started ok. Now today with a boat full of friends it failed to start at all. Changed both filters, bled at filter, injector pump, and injectors, still no start. What do you think is the problem?