engine was running fine , took the boat to another lake 1 week later ,,,, out on the lake 5 minutes and started losing power at 30 mph , barely made it to shore ,,took the plugs out [ wet] put a new set in , worked go for about 2 minutes then did the same thing losing power and would not throttle up,,,,float stuck??????
You may be losing spark on one or more cylinders. An inductive timing light will show the quality of spark on all 4 plugwires. Weak ignition components tend to fail when the engine heats up to normal operating temps.