Pontoon Boat & Deck Boat Forum

1987 harris 24' pontoon. want to install 130 hp johnson 25" shaft.. Any issues with long shaft anyone can think of? Boat has larger pontoons 23" I believe.

i think if i remember correctly pontoons use the longer shaft.

The standard shaft length for pontoon boats is 20 inches in most if not all applications. I ran into the 25 inch shaft issue myself when I purchased a brand new Yamaha crate motor on e-bay for a very good price. Anyway to comply with warranty and installation requirements to comply with Yamaha specs. it was necessary to install a jack plate to raise the motor to the required recognized mounting height. In my case the motors oils reservoir would have been submerged preventing the motor from reaching the proper operating temperature.
The jack plate was designed to raise the motor the required additional five inches in height. But as you can see I still had to raise and use the lower holes in the actual motors mounting plate to get her within the specs. for warranty requirements. And in reality it actually could still use another inch or two more yet because its still plenty deep. Maybe with your motor you'd be OK but if your ever running any skinny water your prop is going to be excessively deep and vulnerable to potential damage. Maybe theirs also a jack plate in your future.

With 23" pontoons you should use a 20" shaft motor.