After getting this 1966 7.5 running, both water pump impellers shredded themselves. I mean every blade down to a wee nub...so instead of repeating whatever mistake I made there,I am trying to steal a whole pump assembly out of another lower unit I have.<br />The verticle shaft and pump came out of my weedless 1966 real easy- it all just slides up...square drives slide right apart.. but this 1963 or so regular lower unit I'm trying to pull apart to steal from... the vertical shaft refuses to part with the lower unit... any tips? Is it just stuck? or do I need to disassemble the lower?