Which OMC models/years will this lower unit fit?

[green heron]

I have an OMC lower unit that I'm trying to identify. I'm wondering which models/years it will fit. Here's the description. <br /><br />• The mating surface mounting to the midsection is about 22"<br /><br />• The mounting bolds are about 4 1/2" wide and spaced at about 5 3/8" apart (both measured center-to-center).<br /><br />• Splines on drive shaft: 20<br /><br />• Length of drive shaft to gearcase: 22"<br /><br />• Splines on prop shaft: 13<br /><br />• Inside diameter of exhaust shaft: 4 1/4" outside diameter (it's<br />difficult to measure around the prop shaft, but this is the best I<br />could do without a large caliper.)<br /><br />• Tip of nose cone to end of exhaust opening: 15"<br /><br />• Propeller shaft: about 3/4".<br /><br />I appreciate your help with this identification!

 

[CATransplant]

Re: Which OMC models/years will this lower unit fit?

Wow! That's going to be a tough one. Any parts numbers on this lower unit? That would simplify things.

 

[green heron]

Re: Which OMC models/years will this lower unit fit?

I don't see a part numbers on the lower unit. It seems to have a v4 propeller shaft, but the mating surface is an inch or two longer than the '73-'77 85HP, 115HP, 135HP models.<br /><br />Do you have any suggestions where the number is stamped on the gearcase?

 

[Dhadley]

Re: Which OMC models/years will this lower unit fit?

If it's longer than those it'll be a 1977 140 or 1978 & up 85/90/115/140. Whats the shift shaft look like at the top?

 

[green heron]

Re: Which OMC models/years will this lower unit fit?

It has the screw-on half-moon shape cylindar type shift shaft.

 

[Dhadley]

Re: Which OMC models/years will this lower unit fit?

That unit will fit a 1977 20" 140.

 

[green heron]

Re: Which OMC models/years will this lower unit fit?

Thanks Dhadley!