I searched the forums for stalling engines and came away with some good leads, even Don S testing. In December I finished restoring a 1985 Bayliner Classic w/ flybridge. This included installing a new 5.7L engine. From the first time out I would get up on plane running at 3200 - 3800 rpm and travel 20 ? 30 minutes down the lake then the engine would just quit, like it ran out of fuel or was turned off. It would quickly restart or if I pulled back on the throttle quickly it would stay running. I could get back up on plane several more times, but the boat would only go 500 feet then the engine would again quit. At this point I cannot get up on plane without the engine quitting even when I pull back on the throttle. The tank is 1/2 to 3/4 full. I would now have to limp back to the launch hoping the engine would stay running with nobody to be seen on the lake for help. I am able to run at 2000 rpm or so in the water at this point for over an hour to the launch with my fingers crossed. The engine mfg thought it was fuel lock, but I could not feel any warm fuel lines or fuel pump, all was cool. The temp gauge registers 135 F. Oil pressure is 40 psi. The gas tank was removed and thoroughly cleaned out during rebuild. I checked the vent and even tried to plane with the fuel cap off.( not to sure what vent size is needed). I initially change out the fuel for 91 octane but nothing changed. I question whether it is the fuel pump on a new engine and the fact that I can run easily at 2000 rpm and some, but not up on plane. It has an electric choke, which is fully open. It seems like a carb problem, but why does the engine run smoothly for the first half an hour. What changes after the 30 minutes on plane. What is the dynamics at 3200 rpm vs 2000 rpm. Is this carb, ignition or wiring?
