Outdrive compatibility - 3.0L and 4.3L

[revansmtl]

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]

Re: Outdrive compatibility - 3.0L and 4.3L

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

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

 

[revansmtl]

Re: Outdrive compatibility - 3.0L and 4.3L

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

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]

Re: Outdrive compatibility - 3.0L and 4.3L

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

 

[Don S]

Re: Outdrive compatibility - 3.0L and 4.3L

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

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]

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.

 

[revansmtl]

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.