89 Merc 35hp Water Issue

[evinrude20]

Well what started as a routine waterpump repair, decided to take the alternate route. Last summer, I was having problems with good water output, really weak dribble at idle, and usually took 10 seconds to start. So I figured my impeller must be in need of the garbage and a fresh installation. So after removing the lower unit, and getting the water pump out, it definately does looked warped. But, I had an extra small hex bolt sitting on the lower unit when I pulled it off. I wasn't sure where this came from, until i twisted the water pump pipe. So sticking the flashlight up into the unknown, I noticed exactly where the bolt came out of. The pipe was only connected on the left hand side so there wasn't a great seal at the top. Does this seem like most of the problem, and does the fix involve disconnecting the whole lower part of the housing?
Thanks!