Is this a special outdrive?

[Brock60]

Got this lower unit and it has a threaded vent hole with "vent" stamped next to it and then another hole that has a rubber plug in it and it's stamped "flush R.H." The holes are at the top of the lower unit if you look through them you can see what would be the inside of the water pump. Thanks guys

 

[Bt Doctur]

A old flushing port in the water pump base since eliminated.

parts 51 to 55

 

[Brock60]

Thanks bt doctur. I looked but couldn't find any info on it. Any idea what years they made them?

 

[Bt Doctur]

That pic came from manual 1, so very old 63 - 73