My lower unit bit the dust, so I went with an SEI and a new drive shaft. Spline measurements and shaft height on the two drive shafts appear to be the same with a micrometer. Old unit will slide in without much trouble, but it no longer has the shift shaft. We can get the new unit up to about 3/4" of being seated. We have jiggled every which way possible. Tried installing with the lower unit in reverse, neutral, and forward. We removed the controls from the boat, so we are guessing as to what gear is engaged on the top end. Is the top of the motor in forward when the top shift cable is pulled more toward the front of the boat? I can see up inside were the drive shaft is and can just barely see the teeth of the splines at the point we bottom out. I assume there is another gear that the drive shaft is not lining up with. How can we get this thing to seat? How do we turn the gear inside top end to help align things? 5 hours. Extremely frustrated.
