Boat has a 1988 OMC 5.0 GM. It would run decent but had trouble starting. Also would only get up to about 3800-4000RPM. Added a fuel water separate, that had no effect on anything as expected. A friend owed me some money and had a sierra universal electric fuel pump kit so he gave me that. I installed that, during the installation I notice my fuel tank did not have anti-siphon on it, also installed one of those. Water Fuel separate is mounted about level with the top of the tank. Fuel pump is mounted about 8in below the top of the fuel tank. Took the boat out to test and had some issues. Starts and idles great. When to give it throttle and everything was good for about 20sec then the engine bogged and died. Would not restart. Pump was not getting fuel. Bypassed the water fuel separate and the pump got fuel. Tried to go WOT again it would bog down with more then 3/4 throttle. And still not hitting WOT RPM. Ran fine just above idle all the way to dock, just after docking and some revving the engine died. After getting the trailer the boat restarted. Loaded and left. The pump is rated at 7psi and 72gph, more then enough pump for a 5.0. I think the pump is running dry at higher rpm's due to the anti-siphon value, doesn't seem like much fuel can flow past that ball. What do you guys think? Any other ideas? Or anything else I should try?