Force 125

I bought my first bass boat and all though it is an older one, it has a Force 125 and didn't need much work. I'm needing help trying to get parts on my lower unit, I was told that the person that had it before it went to auction, tried replacing the water pump but I'm guessing they wasn't sure where or what it was, due to the fact the gears and the rest of the units parts are apart. I don't know where to begin. I need bolts for sure but cant find a parts list or a diagram showing what I need. I'm positive there's parts missing. Any help is appreciated.

http://www.boats.net/parts/search/Merc/Force/parts.html
This is a parts diagram for a 87/125
They are all about the same.
Pics of what you have will help.
Lay them out so we can see what's there.
IF???? Yours has been disassembled then you probably need a factory manual.
It has the specs on shimming.
I have some stuff, maybe I can help.
If it was me, I would look for a used lower that's complete.

You can find them all over.
Just make sure that it's the same length.
They come in 20 and 25"
Since you have a bass boat, I'd think yours is a 20"