I have a 50HP EFI Mercury outboard that is about 3 years old. It has very low hours and I have had no problems until now. Last time out, while running at WOT the engine began to lose power and eventually died. The tank was full. It started again only after pumping the fuel bulb. This happened several more times until I discovered that the engine would continue to run as long as someone was pumping the bulb. Has anyone else experienced this problem? Could it be a dirty fuel filter? Or perhaps the fuel pump is going bad? 