Outdrive compatibility - 3.0L and 4.3L

R

revansmtl

Recruit
Joined
Aug 5, 2012
Messages
3
Hi everyone,

I'm new to the forum and I'm obviously here because I have a problem.

After getting stranded out on the water, I removed and disassembled my outdrive to find that my pinion, forward and reverse gears are all finished.

I have a 1989 OMC 4.3L cobra and I want to know if anyone can help me confirm the compatibility from swamping outdrives from different size motors.

Does it make a difference, is it as simple as keeping the same gear ratios.

I've found an outdrive taken off a 3.0L and want to install it on my boat.

Any thoughts?

Cheers,
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,475
Re: Outdrive compatibility - 3.0L and 4.3L

Does it make a difference, is it as simple as keeping the same gear ratios.
Click to expand...

Ayuh,.... That's pretty much the jest of it,.... Welcome Aboard,....
 
R

revansmtl

Recruit
Joined
Aug 5, 2012
Messages
3
Re: Outdrive compatibility - 3.0L and 4.3L

Bond-o said:
Ayuh,.... That's pretty much the jest of it,.... Welcome Aboard,....
Click to expand...

Thanks Bond-o,

So can I use the 3.0L outdrive?
I did find some posts in the forum saying that the 3.0L is not compatible with the 4.3L.

Thanks in advance
 
Scott Danforth

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
52,851
Re: Outdrive compatibility - 3.0L and 4.3L

the case is the same, the gear ratios are generally different.
 
Don S

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Outdrive compatibility - 3.0L and 4.3L

revansmtl said:
Thanks Bond-o,

So can I use the 3.0L outdrive?
I did find some posts in the forum saying that the 3.0L is not compatible with the 4.3L.

Thanks in advance
Click to expand...

It will bolt on, if that is what you mean, but the gear ratio is wrong for a 4.3. I also believe the 3.0L lower unit is smaller (weaker).
 
Lou C

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
14,178
Re: Outdrive compatibility - 3.0L and 4.3L

What Don said is true, the ratios are wrong, but also the lower unit for the 4 cylinder engines was smaller that the ones for the V-6/V8 cobras. The upper gear housing is the same. The Cobra lower units are very similar to the Johnson/Evinrude lower units, the 4 cyl ones were like the smaller outboard gear cases, the V6/V8 ones were like the V-6 outboard case and the one on the 460 King was I think like the V-8 outboard case. So get the right one, that one will not work.
 
R

revansmtl

Recruit
Joined
Aug 5, 2012
Messages
3
Re: Outdrive compatibility - 3.0L and 4.3L

Thanks Scott, Don and Lou for your help!

That clears things up.

So I'm starting to call some local Marinas looking for either a lower or complete outdrive unit, since the cost of new gears and seals looks like it will run me about the same amount as replacing the whole lower unit.

Does anyone have some suggestions who I could call for a used outdrive in decent shape?
I've been looking online, but I haven't been finding the right unit for a 4.3L.

Thanks in advance.
 
You must log in or register to reply here.
Top