I have a 1964 johnson 5.5 hp cd21a. I want to replace the impeller. I just learned that I have to remove the power head in order to disconect the shift lever. This sounds a little scarey. My first question is, in order to remove the power head do you take out the four bolts under the hood? or is it the six or seven smaller ones on the bottom? I hope that made sense. Will I have to replace the powerhead gasket? And when I get to the water pump can I just replace the impeller or should I replace the housing as well. Please help