I am missing the Prop Shaft on my 1973 85hp lower unit. Where does one get new or even used parts for this? Or even a used lower unit? Where could I order them and is there other prop shafts compatible with this engine? The lower unit itself, Mercury stop making, so a mechanic said you may just have to rebuild it. I have a manual on how to rebuild it but the problem is where do I order the essential parts? Any info would be greatly appreciated! Thank you.