Re: Do I have the right pump?

[Don]

quote amuller:

Yes, there are unknowns here. But based on all said I’m thinking that we have a 1969 leg, with a 1979 or later gearcase. (That based on the four screw holes, the shortened spacer/isolator, etc.) Whoever assembled it used a 3 screw metal pump housing that did not really match the gearcase or the spacer. (But I don’t seen any reason it wouldn’t pump if carefully assembled.)

So it is a matter of using the plastic pump that matches that gearcase, not of trying to use a newer pump on an older gearcase.

What are the differences in impeller key? The one that came out was plain round pin, not the type squared on one end.

What am I missing here?

There is an old-line OMC dealer 20 minutes down the road; maybe I’ll go and see if they are up for a consult.

Again, I’m sorry I brought this up, and now feel I have sent you off in the wrong direction….I do not think you have a 79 gearcase, and again, the 79 water pump parts will not work on an older gearcase….
The difference in the driveshafts is the impeller key….Your current set up has a hole in the driveshaft to receive the round pin that secures the impeller. The 79 set up has a flat spot on the driveshaft that receives a roller key for the newer style impeller…
I agree with Steve.
But, thankyou for bringing up these questions, I have learned some valuable lessons!