I just recieved my new/used lower unit today. I sent the seller my old lower unit, the deal was either he would repair mine or send me a new one. He said my casing was warped and was worried it would not seal. So he sent me a different one.
My problem comes in the fact that either the new lower unit casing is smaller in height than the old one, or the shaft is longer than the old one. When I mesh the lower splines on the shaft into the pinion gear in the lower unit the key way for the woodruff key for the water pump impeller is about a 1 7/16" to high, which will not let the water pump housing bolt to the lower unit casing. I also left the water pump off and with the shaft in the lower unit, fit the upper splines into the power head. I had about a 1 7/16" gap between the mating surfaces of the lower unit and the motor. I'm sure i have got the shaft engaged into the pinion gear, as i have checked it multiple times by measuring.
I was wondering if there is a possibility of a difference in the shafts of the old and new unit, or if there is a difference in the housings. My thoughts are that the shaft is different, either in length or the position of the key way on the shaft. Or maybe I'm just not seeing something. Any help would be greatly appreciated.