help selecting prop for 1548 all welded jon boat

[waterfowler15]

motor is a 1992 johnson 20 converted to 30hp, i do have a blind on it and usually have 2 guys and gear but i wanna go fast!!! any ideas would be great, 11.25x17? ,11.25x18? or is that wrong thanks guys

 

[jestor68]

Re: help selecting prop for 1548 all welded jon boat

The biggest prop I see listed for that motor is a 15 pitch.

More info on exactly what brand boat you have and how much it weighs would help.

Considering all the stuff you plan on having on it; I'm thinking a 13 pitch.

 

[steelespike]

Re: help selecting prop for 1548 all welded jon boat

First of all any prop change requires a working tach and gps speed.An induction tach is easy and reasonable.
Many cells have a gps app. The motor needs to operate within its rated rpm range at wot.5200-5800.
You should do some test runs with the present prop lightly loaded to see if the set up is working.
As you increase pitch it becomes harder for the motor to push a load.
I think a 12 or 13" prop seems reasonable.

 

[waterfowler15]

Re: help selecting prop for 1548 all welded jon boat

the boat is a 2004 alumacraft waterfowler 15 ,boat weighs 330 lbs no motor or anything so its heavy,i do have a gps app, navionics so i can tell speed,no tach tho which one do i look for? i know im better than my 1976 evinrude 25 due to the bigger head and exhaust thru hub.... but no open water here yet to tell i just bought a this motor and made into a 30 it will need a prop so may as well get a decent one seen a couple ron hill props on ebay but not sure for the price how much more speed we are talkin about