need prop help

[shavedhead]

Just bought this 18 ft. pontoon with 1999 merc. 50,motor runs great, have made 3 trips to lake now and have information on rpm and prop, The prop says F10.13x15P running at wot 4200 rpm. 17.4 mph according to gps.motor says 5500 rpm is max.there is a sticker on foot that says 12x22 1.83:1 . My prop is alum. and in my opinion needs to be replaced, my question is should I change size and pitch to get best preformance. the boat is used for riding not pulling tubes or anything.Of course I would like to get a little more speed but mainly just want to run at what is best for engine. Thanks for your help.

 

[steelespike]

I think a 11" prop should do the job.
The 12 X 22 Is the gear ratio 1.83.
You may want to check out the Merc Spitfire 4 blade.
Ive seen spitfire test that ran a tiny bit faster than a already fast boat.

 

[shavedhead]

i will look into 11" thanks for your help