water pump leak

[Carl]

I have been having cooling issues on my 1988 mercury 150hp and have been eliminating issues one by one, but today I came across something I thought was odd and wonder if anyone else has experienced it too. So I dropped the lower unit and hooked up the water muffs to the intakes just to see how the water flowed figuring I could determine if my particular issue was in the lower or the upper half of the engine. Anyway, I noticed a lot of water leaking from somewhere below the pump upper housing - near the front of the pump. I was unable to stop or even slow it down no matter how tight I cranked the water pump nuts. I didn't want to go crazy tight on the nuts, but it was much tighter than I would normally go on a water pump housing. I replaced the lower half of the water pump a month ago. Not sure where to go from here. Any advice?

Thanks

Carl