Prop Difference

B

bufordg

Cadet
Joined
Oct 18, 2012
Messages
28
I have a friend who wants to change props but the only one we can find with tghe right pitch he wnats is a 4
blade. Is it possible to change from a 3 blade to a 4 blade. Are they a benefit with either.48 hp johnson
 
R

rallyart

Lieutenant Junior Grade
Joined
Jun 7, 2008
Messages
1,177
Re: Prop Difference

You can change from a 3 to a 4 blade without issue. The shaft size and mounting have to be compatible and the diameter has to be similar so it won't interfere with anything. Four blades usually mean more surface area so they might not be as efficient and they might have more low end push. It should not be a problem if it bolts on correctly.
 
jestor68

jestor68

Commander
Joined
Jun 12, 2012
Messages
2,308
Re: Prop Difference

Have you checked the iboats prop section?

For the Johnson 48, props are available in 1 inch (pitch) increments from 8-15"; and then 17 and 19".

The 4 blades are 10" pitch and below.

That should pretty much satisfy any requirement.

When going from a 3 blade to a 4 blade, you drop an inch of pitch to maintain WOT rpm.
 
S

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Prop Difference

Pitch shouldn't be a problem.
He may find the diameter to be different.
If not extreme if the prop is intended for his motor it will be right.
You may notice that sometimes as pitch goes up diameter goes down.
If he's changing props now may be the time to fine tune the setup.
Get us the info requested in the stickys at the top of the prop forum.
 
You must log in or register to reply here.
Top