[Billigan1]

Well this could be a very long story but I will sum it up. Boat it used, great motor for about a month, would not idle high enough to place in gear, it died. Took it to what I though was a reputable shop. They did 3000 worth of nothing to it and had the same problem 2 hours later. Blew the power head, burned 6 and 2 my gues is ran to lean or oil pump died. Pulled engine rebuilt it myself, new everything, done the right way, even reeds. Nice turn out, strted right up. I am on hour 10 of break in. Motor bogging. Switched to external tank, changed water separator, ran like a top for 6 gallons. Did some idle trolling for about a mile worth of no fish and now same problem again on external tank. I am running double oil. Cleaned plugs, ran tad better but running rough no power. 90lbs on fuel pump, regular opening, new pulse pump pushing 4 lbs like it is supposed too. New trigger on rebuild, all 6 are hitting. Clueless here! Running as if plugs are foul, but they are not. Don't want to kill new powerhead, HELP. I understand this motor, I am no expert but understand it, read the manual cover to cover, new fuel lines, so much new, same bug. Any takers?

[CharlieB]

First, ensure that the fuel pick up in the vapor separator is clean, no restriction, same with the water filter.

Then take that pressure gauge for a ride and watch the rail pressure as you hit the throttle, ANY sign of pressure falling off shut down and replace the high pressure pump.

High pressure pumps willll always show pressure at idle and light loads, but when the max flow required for high RPM loads, well, it ain't there. And you lean out and melt pistons.

Also double check all hose routing from fuel tank to primary pump, one zip tie too tight restricts flow enough to go lean at WOT.

[hkeiner]

I would also check that the fuel lines upstream of the motor are not causing a problem. If you decide to test for this, the below guides may be of help. The guide is most applicable to a carbed motor but I think that the test for fuel line restrictions may still apply to EFIs. At least you can eliminate fuel line restriction as a possibility.