How to tell what lower unit I have?

[treeeman00]

Looking for info on how to tell what lower unit I have. I had a guy that works on OMC outdrives come and adjust my shift cables and he said I had a 4 cyl lower unit on the upper and my engine is a 350 chevy. How do I tell for sure what lower unit I have. He said the diameter of the prop shaft housing is the difference.

 

[Boomyal]

Re: How to tell what lower unit I have?

OMC units spanned a number of years and had several iterations. Impossible to answer your question without, at least, a year.

 

[Howard Sterndrive]

Re: How to tell what lower unit I have?

13 tooth spline propshaft = 400 series for 4 cyl
15 tooth spline propshaft = 800 series for V6 and V8

 

[treeeman00]

Re: How to tell what lower unit I have?

I do not know the year for sure. I bought the outdrive separate from the boat. Wasn't there a 19 splined shaft? The guy that worked on the boat seemed to think that the prop shaft housing was from a 4 cyl because of the diameter. He thought it should be larger for a V8. Is there anyway to determine?

 

[fuzzybob]

Re: How to tell what lower unit I have?

Treeman,
You must not have read Howard's post, #3. Pull the prop off the prop shaft and count the splines.

 

[treeeman00]

Re: How to tell what lower unit I have?

yes I read his post and that's why I asked about the 19 spline count. I thought I read somewhere about 19 splines on the prop shaft but I may have been mistaken

 

[Howard Sterndrive]

Re: How to tell what lower unit I have?

Is there anyway to determine?

not without getting off the internet and going outside. If you count 19 we'll look into it.

I swear some folks hate to hear that the solution to something is simple.

 

[treeeman00]

Re: How to tell what lower unit I have?

well I got off the internet and counted 13 and drained the oil and counted both gears. Got 16 and like 19 or 20 (couldn't count all of them with the outdrive installed with one person) so basically I got screwed when I bought the outdrive but it was my fault cause I didn't research enough and didn't know what I was buying. The guy told me it came off a V8.

 

[Howard Sterndrive]

Re: How to tell what lower unit I have?

someone will buy your lower unit or the whole drive- craigslist or kijiji
now that you know what it is and can figure out the ratio, you'll have the best info in the classifieds, so you should get lots of qualified calls.

then you can get a V8 unit or do the SEI conversion to merc alpha type drive

 

[Boomyal]

Re: How to tell what lower unit I have?

......or do the SEI conversion to merc alpha type drive.....

What's this about? For a stringer?

 

[treeeman00]

Re: How to tell what lower unit I have?

ya howard that's what I planned on doing. Going to post on craigslist. Hopefully I can get my money out of it which im sure I can. Im in it at $700.00. Id love to put a mercruiser on but its pretty expensive I think? Honestly im sick of working on it and want to go the easiest route at this point. Hopefully ill get it going before the seasons end I hope. Thanks guys for all the help. I have learned a lot thanks to this site and its members.

 

[Boomyal]

Re: How to tell what lower unit I have?

.... Honestly im sick of working on it and want to go the easiest route at this point. ....

If you think that it would be any different with an older Mercruiser, you are highly deluded. Stringer OMC's have fewer variations, are less complex, and are no different in their need for specific knowledge requirements than any other drive.