I have taken the lower assembly apart as it had water in the oil, and am replacing the seals and going a general clean up. When trying to assemble the power head to the pump section, I can not seem to convince the pump section to set fully down on the power head. I don't want to be assault either section with a hammer, so what is the trick to getting it to slide into place?, the shaft turns freely and it is apparent that the drive gear is not contacting the driven gear at the point the assembly stops and refuses to slip into place. I have three different books on the Chrysler 105 HP motor, and none say anything exceptional about the reassembly of the two units. In fact it seems rather straight forward when i read about it. I am not a boat guy, but I have assembled a lot of engines, gear sets and axle bearings in my life so I thought this might be possible without going to a new school.