Need the stock size of prop for OMC Cobra

dodge1971340

Petty Officer 3rd Class
Joined
Mar 23, 2006
Messages
75
Hi I need the stock size and pitch of a omc cobra props for 1992 for 19' Caravelle ob boat 4.3 and 5.0 I have mismached drive and motor i have a 5.0 motor and i will have a 4.3 out drive. just trying to get the prop close with out overreving it. I looked in my seloc manual couldnt find them. i know the gear race are about 10 off the 4.3 are 1.68:1 and the 5.0 are 1.59:1. any help would be apprectated Good day and God bless!! GP
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: Need the stock size of prop for OMC Cobra

You're in uncharted territory and the drives have no standard prop. It all depends on the boat it's mounted to. I'd guess to start with a 21 pitch.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,090
Re: Need the stock size of prop for OMC Cobra

My Guess would be to start with the Largest prop you can Find..........<br /><br />The Difference between the 2 ratios you stated is about 6+"s of Prop Pitch............<br /><br />And,.... In My Experince,..... It'll put you Just Over(Bigger, higher pitched) any standard easily available Props........<br /><br />In other words,..... You'll be needing a Custom built Prop......
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,053
Re: Need the stock size of prop for OMC Cobra

I can tell you that my 88 4.3 Cobra came with a 14 1/2 x 19 prop,and the overall drive ratios are 1.68:1 for the 4.3 and 1.50:1 for the 5.0. This is from my 88 OMC Owner's Manual.
 

dodge1971340

Petty Officer 3rd Class
Joined
Mar 23, 2006
Messages
75
Re: Need the stock size of prop for OMC Cobra

Hi guys!! thanks for the input.. talked to some marine macks thay said about 21 pitch also, and with lou's size boat same as mine 19' and running a 19 pitch I think the 21 will be prity close to were i need to be with 5.0 Thanks again you havent seen the last of me!!! GP
 
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