I bought a used 2011 pontoon boat with a same year Honda BF50D from a boat dealer this summer. I had it for a month during which it ran well, then suddenly started running poorly at full throttle. The dealer has been real good at working on it, no charge, but not getting any results on a solution. They feel that the rev limiter is shutting the engine down. It was sent to an authorized Honda service dealer, where they dropped the engine an inch and changed the propeller with no change.
I'm wondering if there isn't another problem that's being overlooked? I read about a fuel pump, or pump diaphragm possibly being an issue?
Any suggestions would be appreciated.