I have a 1984 Johnson 15 horse serian number E5897783 that I just bought. Water seems to be cirulating very well. It has a nice stream comming of of the nipple, but the shaft seems like it is way to hot. A lot warmer then it should be. where the exaust is a little bit of water spits out of that that is very hot. The motor it self is not hot. I have replaced the Oil in the lower unit. The guy I bought it from works at a boat place and said the just replaced the water pump ( I have no idea if thats true). The screen is clear. Is there something wrong with the shaft being that hot, and how should I look to fix it? Thanks!