Posts: 3484
Location: Elk River, Minnesota | Hiya,
In most cases, an increase of 1 mph is roughly equivalent to an increase in about 10hp given all things are the same. Engine displacement can help with low end torque and a little more "umph" felt while accelerating...but as for top speed, all are pretty close to being the same.
I would agree that if your hole shot is slow, you are over-pitched on your prop. If memory serves me correctly, that motor has at lowest a 2:1 gear ratio but I would guess it is more around a 1.85:1 gear ratio. The closer the two numbers are in the ratio, the smaller the pitch one needs to get good overall performance...especially out of the hole...top end not so much. So...your 14 pitch, I would say is probably about 2 - 3 inches too much, with a 12 being solid potential. On that rig, I would also not be surprised if a 10 would do really well also.
Friend of mine has a 50 4 stroke yamaha on an older model Alumacraft Dominator (way way way underpowered) and runs an 11 pitch which does alright. He sees about 26 mph.
So...repower for a couple thousand and an extra mph maybe and a little better hole shot, or re-pitch for around $150 to get your hole shot and maybe a loss of 1 - 2mph on top end?
I, myself would take the hole shot over speed, because if you get into a blow, having the low end power to the engine is much more valuable...especially in following seas. the ability to drive up a wave to avoid swamping from the rear is a HUGE benefit to have.
Steve
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