I have a 1982 50 hp merc. The old impeller was chewed so I bought a new water pump kit. I never installed a water pump before and this was a real bear of a job today with me dropping the lower unit five times with a multitude of problems. The water pump installed without much problem but upon tightening the water pump housing bolts the drive shaft appeared to bind up sum and became hard to spin. I reinstalled the lower unit and the drive shaft was so tight that the starter motor could not spin the motor, obviously the impeller is binding up the drive shaft somehow. I installed the splines in the proper direction by turnin the drive shaft clockwise while pressing down on the waterpump cover. <br /><br />The real tough part of this job came when I tried to reinstall the lower unit. This lower unit was real tough to put back together. I did it five times today. the biggest problem was to line up the splines on the shifting shaft with the female end of the shifting rod. The rod is danglining around while you are drying to line up the heavey lower unit. You can barely see what you are doing. The moves about while you are trying tho get the splines in. I seem to be getting it out of sink because the shifting controls donot appear to work once the lower unit is installed. How do I get the foward and reverse lined back up with the shifting rod. There has to be an easier way to do this. Can I loosen the shifting rod at the top and drop it down onto the shifting shat and then reattach it at the top once i have the lower unit in place ?<br /><br />As anyone can see I had a really hard time with this. I have a book but the diagrams are not detailed enough to tell me if I go it all back together right. Can anyone walk me through this.<br />thank you