Boat "hops" when motor is tilted out

[imported_maverick]

I don't have power tilt/trim. Yesterday, I tilted my motor out one more hole. As soon as the boat planed out, it started "hopping". The bow was rising and lowering non stop. Stopped the boat and tilted the motor in one hole then it stopped "hopping". Never had this problem before. Anybody have an idea what causes this.

Motor: 1977 70hp Johnson
Boat: 15' fiberglass tri-hull

 

[JB]

Re: Boat

Re: Boat

It is called "porpoising", Mav.

With the engine tilted out too far it keeps trying to raise the bow, goes too far and the bow falls back. Repeat.

It is normal outboard or I/O boat behavior.

 

[Jdeagro]

Re: Boat

Re: Boat

Why did you want to tilt it out more?

 

[imported_maverick]

Re: Boat

Re: Boat

Just curious about the boat/motor performance

 

[imported_maverick]

Re: Boat

Re: Boat

Thanks JB. That's good to know.

 

[Chris1956]

Re: Boat

Re: Boat

Maverick, Just so you know, maximum speed on a boat occurs as you trim out, just before the boat porpoises.