Prop size

[reelapeelin]

Originally Posted by Joker2

I checked all the cylinders pulling the wires one at a time didn't really notice the Tach move, but I did hear a drop in the engine with each one. Also on the lower Starboard plug there was a little build up of black. This happened once before when I was running double oil on break in, just thought it was the extra oil fouling the plug, should I be conceerned?

Joker, these are deep V hulls, which means there is a lot of planing surface on the water which means resistance...IMO they need a large diameter prop to get all the push against that resistance...I used a 15 1/4" x 17 for that reason and was completely satisfied that my motor was getting all the prefomance possible on that hull...The only reason I didn't use a 15 1/2" diameter was that it was a little too heavy and caused a rattle in the lower unit, but your motor should handle it...you didn't mention SS or alum...use SS for best performance...hope this helps you find the right prop...sometimes it's not easy...

[Joker2]

Originally Posted by reelapeelin

Joker, these are deep V hulls, which means there is a lot of planing surface on the water which means resistance...IMO they need a large diameter prop to get all the push against that resistance...I used a 15 1/4" x 17 for that reason and was completely satisfied that my motor was getting all the prefomance possible on that hull...The only reason I didn't use a 15 1/2" diameter was that it was a little too heavy and caused a rattle in the lower unit, but your motor should handle it...you didn't mention SS or alum...use SS for best performance...hope this helps you find the right prop...sometimes it's not easy...

the prop on there is a 15- 1/2 X 15 aluminum. She really jumps onto plane, since I had it repitched I can get 5000 on Tach ( if Tach is correct ) but doesn't feel that powerfull only 30 mph. on GPS. Last year I got 30 mph at 4000 RPM. I will do a compression test on all cylinders, if that is good I will research if doing a seafoam treatment that everyone talks about on this forum will be safe to do to my engine. maybe that is all it needs.