No torque past 3,000 RPM or when turning

[RickFinley59]

Took my 19' Bayliner w/3.0 Mercruiser out for the first time. Ran great up to 3,000 RPM's. Engine revved but boat wasn't pulling. Same thing happened when under a load due to turning. Pulled prop and had it checked for a spun hub, but the tech said it wasn't spun. Any ideas? When not under a load, the boat ran great!

 

[Rick Stephens]

If it isn't a spun hub, and the rpms goes up, then it could be a coupler at the engine flywheel that is going. Usually that leads quickly to the motor speeding up and the boat not going at all. And a coupler will smoke or smell as the rubber melts.