%0hp Johnson prop question

[todster]

I have a Bayliner capri 14.5 with a johson 50hp 1972 large gearbox. The old force 50 junk would do about 32 mph on the speedo (inaccurate I'm thinking). The johnson has a 14x13 on it and I put an omc tach on it set to 6- check it with hand tach and really close. I can nail it and it jumps onto plane fast. The tach says 6300 when I nail it might go higher but didnt dare try although I dont think much higher. 5400 Rpm is about 2/3 throttle and gps says 23 mph, the speed increase at 6200 is not much more but it is an immediate lurch forward. Should I go with a 15p or 14.25x17. i found a new 13.25x17 on ebay for $25+s/h. A 15 cupped would be the same as a 17 I think. Not sure if my 14x13 is cupped. The 13.25x17 is just a j-81. What should I expect from this setup for a speed with say 3-4 people? And what prop. The 14x13 will pop right up on plane with 3 in boat and 2 on a tube. Also have a 40 hp lark electric shift with 23" transom- whats that worth and a 50hp force awesome powerhead with no lower. My 18 Fleettwin is staying.
TIA

 

[ezeke]

Re: %0hp Johnson prop question

You will want to get the WOT RPM down to max around 5800, and the 13-1/4 X 17 will probably put you close. You will not have the same hole shot, though, so you might want to try stepping up to that first.

 

[steelespike]

Re: %0hp Johnson prop question

I have a feeling that may have been on a pontoon or other hard to push boat.I suspect the gear ratio requires a higher pitch than a normal 50.
As suggested a 17 should put you in the ball park.If your going new you might check out the Turning Point Hustler.The oversize gearcase will slow you a little but should be as fast as the Force.

 

[todster]

Re: %0hp Johnson prop question

12:32 gear ratio. The Force 50 was a toy compared to the Johnson 50. Its like comparing oranges(more like a lemon) and a watermelon. The speedo on the boat had to have been way off. It didn't work when I put the Johnson on so thats why I used the gps. Its just kind of hard to believe that this would use the same size as pitch as a 16 or 18' boat with an I/O