4.3 OMC vs. 5.0 OMC outdrive

[redone4x4]

When i got my boat, I was told by the previous owner that the outdrive had been stolen and a replacement was put on. I just realized recently that with my 5.0 305 engine, I have what is labeled as a 4.3 OMC outdrive. Is this the same outdrive they used on the 5.0, or do I now have a mismatched engine with a smaller outdrive? The boat runs fine, I havent had any problems other than the routine maintenance.

 

[Summer Fun]

Re: 4.3 OMC vs. 5.0 OMC outdrive

Edit went and looked at manual. :redface:. You'll be ok with it.

 

[redone4x4]

Re: 4.3 OMC vs. 5.0 OMC outdrive

Nope you've got to regear it for that motor

well, its been on there for the 4 years that i have had it, and i havent had any problems. is the final drive ratio on the 2 different? I have a 14x19 hustler prop and I can run about 4500 rpm wide open which is plenty for me. I just noticed it recently, Im starting to freak out a bit over it. I cant afford to replace the outdrive with the 5.0 one if thats what i need, but like i said it seems fine so far now.....what exactly are the differences?

 

[Gary H NC]

Re: 4.3 OMC vs. 5.0 OMC outdrive

As long as it is turning the rpms you need and it is.......don't worry about it.

If i remember from my old OMC manual the 5.0 and 4.3 used the same gear ratio..(wish i still had that book)...
Either way you are not over revving the engine and the speed is ok be happy

 

[Summer Fun]

Re: 4.3 OMC vs. 5.0 OMC outdrive

My manual says , the 4.3 21/20 / 5.0 21/17. So i guess you're ok .:redface:

 

[redone4x4]

Re: 4.3 OMC vs. 5.0 OMC outdrive

okay sounds good. does anyone know if its actually a different outdrive? is it a "smaller" one or one thats meant to handle less power? are there different model numbers for the 2 outdrives?

 

[danond]

Re: 4.3 OMC vs. 5.0 OMC outdrive

It's the same.

 

[redone4x4]

Re: 4.3 OMC vs. 5.0 OMC outdrive

It's the same.

thank you! I was really stressed out for a little while there.....but there should only be about 30-40 horsepower difference between the 2 engines so I was hoping it was the same.

 

[danond]

Re: 4.3 OMC vs. 5.0 OMC outdrive

You're welcome. Your original OMC service manual purchased from eBay must be still in shipping, eh?

 

[redone4x4]

Re: 4.3 OMC vs. 5.0 OMC outdrive

You're welcome. Your original OMC service manual purchased from eBay must be still in shipping, eh?

ya i guess. I have a Seloc manual, but its at work and I wont be back there til tuesday. I kinda panicked when I saw the 4.3 on the side of the outdrive haha.