Re: 1960 35 hp Gale water pump problems
If the water pump is sealed... housing to plate, plate to gearcase, and the impeller is indeed new, that is... you just installed it "new", and the water tube has not been pushed up accidently but is rather inserted into the water housing grommet properly... the water pump has to be functional UNLESS the engine has a failing head gasket which would allow the combustion pressure enter the water jacket area which would result in a stalemate condition.
Stalemate.... Water coming upwards, combustion pressure traveling downwards. Where the two meet, the water can go no further.
The water pump is not a self priming pump... meaning that it must be covered with water in order to start the pumping action. Whether in a barrel or on a boat in the water, the water level must be a couple inches at least above the water pump area.
If the impeller was installed new some time ago and the related gearcase has just been sitting around for quite some time, the possibility exists that the blades have taken a set, that is... they are frozen in a curved/bent position (Not Good).
One other possibility that I can think of.... Sometimes the water tube bevel can catch the edge of the water pump housing grommet. When this happens, as the gearcase is forced upwards, the tube forces the edge of the grommet to fold over, effectively creating a shut off valve.
Let us know what you find.