Long shaft to short shaft Mercury 1150 conversion?

K

kungpaoshizi

Petty Officer 1st Class
Joined
Apr 29, 2013
Messages
221
I've been looking around for info, but everyone seems to want to go from short shaft to long shaft.. :rolleyes:

I saw a post on here about a Mercury 800, it has the same midsection, different gears (to warrant a prop change), and a few slightly different components elsewhere.

Is there other models to consider as well that are compatible with a '77 1150, perhaps without a gear difference?
Is a short shaft even advisable for a 1150, or just a medium shaft because of speed differences or something?
 
M

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
Re: Long shaft to short shaft Mercury 1150 conversion?

It all depends on the BOAT height transom you have. 15" short, 20" long.
 
matt167

matt167

Captain
Joined
Sep 27, 2012
Messages
3,700
Re: Long shaft to short shaft Mercury 1150 conversion?

short shaft 6cyls do exist but not many. You could use a 65-85hp short shaft 4cyl midsection and other parts. Gear ratio is 2.3:1 for the 4 and 2.0:1 for the 6. It will never run full potential with the lower ratio. If you want 115hp on a 15" transom, get a jack plate
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,158
Re: Long shaft to short shaft Mercury 1150 conversion?

Kung, I had thought your transom was 20". There are not many boats rated for 115HP that have 15" transoms.
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,158
Re: Long shaft to short shaft Mercury 1150 conversion?

If you hang a 15" shaft motor on that boat, you will not get on plane.....
 
Faztbullet

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,619
Re: Long shaft to short shaft Mercury 1150 conversion?

Kung the dealership I worked for in 1979 sold Venture bass boats and you need a standard 20" motor. That boat with a 4 "jack plate( 6" reversed) with a 20 Turbo ran in the high 40's -low 50's depending on load.
 
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