prop size for 1999 40hp 15 ft

R

randy0050

Cadet
Joined
Nov 2, 2006
Messages
12
1999 40hp johnson 15ft 4' bottom sea ark allweld. The boat seems very light. When thottled up it can throw you out of the boat. Top end has something to be desired.It is a tiller, had a 180lb person on the bow. From a dead start it jumped out of the water and was on step in 2 secs . What is the proper all around prop pitch for this boat? The boat is max rated for a 40hp , 4 peaple ,and 585 lbs total. The prop size i have now is unknown as i looked on the fins and barrel and have seen no #'s. What i am looking for is better top end and fuel econemy for the long trip.
any help ?
Randy
 
Silvertip

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: prop size for 1999 40hp 15 ft

Chances are that motor was delivered with a 12-3/4 x 15 pitch, cupped, aluminum prop. Look inside the hub for the diameter and pitch. On a light boat such as yours, you can probably run a 17P. However, since you provide no wide open throttle rpm or speed information, there is no way we can advise on exactly the correct prop. Whatever prop you choose, fuel economy will change very little.
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: prop size for 1999 40hp 15 ft

Please repost this in the Prop Forum.
 
R

randy0050

Cadet
Joined
Nov 2, 2006
Messages
12
Re: prop size for 1999 40hp 15 ft

It is a steel prop as i stuck a magnet on it. I think i will just move weight around,(as in fuel tank,ice chests,cut a hole in the front bow and stick some stuff in there), and see what she does.Thanks silvertip for the advice. d:) Will let you know what happens!
 
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