Reply To: 1948 Gale Hiawatha 5HP

[frankr]

Rest assured, those pumps do provide plenty of water if working correctly. I think somebody was trying to re-engineer it with those extra parts.

Let’s start over at the beginning. The important items to consider are the fit of the rubber rotor. It should fit the brass eccentric closely, and just touch the inside of the pump housing at some point as it goes through it’s wobble action. Also, it should contact the inside of the cap cover, in other words no space between the rotor and cap cover. Lastly, no big wear or big pits..

How it works: At some point in the rotor’s wobble cycle, a gap between the rotor and housing fills with water through the rectangular slot in the cover. As the rotor continues through the cycle, the gap moves around to the other side, taking it’s gulp of water with it. Finally, the gap disappears, squeezing the water up through the pump outlet and water tube. As long as the rotor is touching the housing on the outside and proper height, the water will not escape from the gap as it moves from one side to the other. That is it is a positive displacement pump. One last thing, the tab on the rotor does not pump anything,, it only separates the inlet side of the pump from the outlet side.

The propeller— As the motor is running and moving forward through the water, notice the pump inlet as facing aft–away from the water flow direction. So, the holes in the prop are on the pressure side of the prop blades, which feeds water toward the pump inlet. Low tech, but so simple that it works.

Now for that 90 degree turn. I haven’t had that many apart to be intimate with that part. But I think I have some pictures. Will look.