What prop to use for small 40hp boat

[eveneman]

Hi - I've put together a 14' aluminum boat with post seats and a steering console powered by a 1987, 40hp johnson outboard. My problem is, with three adults in the boat, it planes VERY quickly and I'm worried about over revving the motor (no tach). I can't tell what pitch the current prop is but it was on a much heavier 16' fiberglass boat previously. I've been looking around am having a hard time finding something to match my boat/motor combination. I found the following light load props so far:

12 x 16" pitch stainless
11 3/4 x 17" pitch aluminum
11 3/4 x 19" pitch stainless (from your site)

Any recommendations to possibly gain some top end speed and lower my WOT revs ?? All thoughts would be appreciated.

Thank you,

Erik Veneman

 

[steelespike]

Re: What prop to use for small 40hp boat

You shouldn't make any changes without your present prop size(usually on the barrel or under the nut.) max rpm and speed.
A tinytach can solve the tach issue and a borrowed gps for the speed.
The wrong prop will give poor performance,mileage and could damage the motor.