Water will slobber out the slots about half way down when running. Yes, the exhaust blows it out. 24:1 is correct, althjough originally it was 16:1. Your choice, really. The motor was made by Gale Products, under a bunch of brand nanes. Spiegel Brooklure was one of them. All the same with different trim parts...The water pump is forward of the propeller. It is what we call a "wobbler pump". The rubber impeller, properly called a "rotor" is part number 550040, available from Evinrude dealers OR Brian Wilcox makes them
http://www.chrystine.com/impellers/order.html
Grease leaking out of the lower unit contaminates the pump and makes the rotor swell up, then it doesn't work any more...