I've posted a couple threads regarding overheating on my 98' Moomba...Recently I came across a thread on another website asking for advice on replacing an impeller. My question is this, does a new impeller have to be hammered (seated) on the shaft of the raw water pump? I've noticed the impeller sticks out of the housing a bit (nothing major) upon replacing prior impellers. Could this possibly be causing my impellers to fail prematurely causing my overheating problem. Any advice/info would be greatly appreciated!