The falling on its face at wot has been going on since I purchassed the boat 2 seasons ago. I replaced the cap rotor button plugs and plug wires last season. This did not effect the issue. Also replaced fuel pump and and check valve and the water seperator twice. Before the last round of changes ie: metering rods plugs and prop I could only pull about 4000 rpms. With the change of these things I was able to achieve 4400 rpm but thst is when the backfire started.