matching boat and motor

[plugin' away]

Hi,i I have a 14 ft fiberglass, Winner boat that i was using an '86 25 johnson long shaft. This combination did well for two people but was insufficient for three people.(wouldn't plane) I have changed motor to a 35 hp '82 Johnson short shaft and this motor although rated at 10 hp more is less effective and doesn't even plane the boat with two people in it.
The motor seems to to opperate well but seems under too much load and won't wind out to top rpm. I have tried to ajust the trim pin and no luck. Any suggestions would be greatly appreciated. Thanks, G

 

[malta]

Re: matching boat and motor

my guess would be the length of the shaft. The prop would need to be just below the hull, to allow maximum effectiveness for the prop to give the thrust to the boat - if the short shaft is not giving the same free flow of sea to the prop, then the extra power available with the 35hp is being lost (or even making performance worse off!). I had a 12.5 ft fibreglass boat with a long shaft 9.9 johnson, and we used to chug around with 4 people on board pretty happily, but when alone, i used to fly!