evinrude/johnson prop interchangability?

1961_lonestar_holiday

1961_lonestar_holiday

Seaman
Joined
Jul 15, 2010
Messages
61
i have a 9.9 i have a 14' lightwieght boat that goes pretty good with the 10" pitch prop, i think it will pull a 12" if i can find one.

from the i-boats site i see a 14 hp made in 1988-1989 has a 10" diameter and 12" pitch with a 13 spline shaft. is the shaft diameter the same? anyone KNOW that it will or wont work?

thanx in advance!
 
S

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: evinrude/johnson prop interchangability?

What year is your 9.9?
I don't think the 12 is a good bet. You should get a Tinytach see what the motor is running with rpm and gps speed.
You shouldn't be changing props without a tach anyway.
A 2" pitch change is pretty extreme with a little motor.
Describe your "light weight boat"?
 
1961_lonestar_holiday

1961_lonestar_holiday

Seaman
Joined
Jul 15, 2010
Messages
61
Re: evinrude/johnson prop interchangability?

my 9.9 is a 72+ idk the exact year. it has a fairly recent rebuild on it runs great. the boat is a row boat/jon boat v-hull 3 rows of seats. i can pick the whole thing up over my head so it dont weight too much (although i am a beast)

i know what you mean about small changes with this small motor, i bought a 7 pitch 10" dia. 4 blade based on recomendations from this forum to push a much heavier 16' alum boat and it is wayyyyyyy to little pitch.

but the guys that build those little mini-most/mighty-most 8' racing boats must get the right prop to make them things go so fast.
 
S

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: evinrude/johnson prop interchangability?

The 9.9 appeared in 74.
Lets assume its a 1436 at 145lbs.Is yours rated for 15hp? And you can get it over your head. I figure your total weight is about 570lbs.
Assuming you indeed are a beast probably @ 250lbs.
Not really light also if its a Jon it probably has about 4 or 5 keels not the best to push through the water.
 
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