Rancherlee
Chief Petty Officer
- Joined
- Jun 6, 2006
- Messages
- 621
Decided to leave the 87' johnson 28spl on the pontoon boat for now instead of taking the 70hp Johnsuki off my fishing boat. I need a new prop for the 28spl as it still has the "shipped from the factory, light weight boat, 9x12" prop on it with a few decent dings in the blade. I bought the pontoon from the original owner and he said it was the " prop that came with it new in 1987 " Needless to say the motor lugs bad. I hooked up my Multimeter with a tach lead to the bottom plug wire and I was turning 4000rpm on the nose with 3 adults and some fishing gear while moving 14mph on the gps. The toon' is a 20' Kennedy with an open deck (NO furniture, only railings and captains chair/console). Its rated for a 70hp max, has octagon shaped pontoons, and weighs 700# with no motor. My local dealer has no used props for me to try since the Spline drive non-thru hub propped motors are pretty rare so I need to order a new prop. My options are 9x12, 9x11, 9x10, 9x9 and I'm thinking I may need to drop all the way down to the 9x9 to hit the high end of my 4500-5500rpm window.
Also, what kind of prop slip should I expect with a pontoon, I'm assuming more than a aluminum fishing boat but you know what happens when you ASSuME.
Also, what kind of prop slip should I expect with a pontoon, I'm assuming more than a aluminum fishing boat but you know what happens when you ASSuME.