Recently (2 days ago) bought a used (very used) boat, 1975 Glastron 15 ft. with a 1973 Evinrude 70 HP. Solid boat and motor runs good, that is, until you put it in gear to back off the trailer. 2 things occur, the gears are backwards (reverse is forward and forward is reverse) and once a load is put on it, it dies. The individual I bought it from (yes, a dealer) just this last week replaced the lower unit. I did get it to somewhat run in the water, in gear, after bumping up the idle. The motor runs great with a hose hooked to it and even in the water without being in gear. Is there a simple fix I can make to this thing or does it need to go back to where I got it. It was pretty much an "as is" deal and with what I see from initial outing, I really don't want to deal with this guy too much.. Could this possibly be an incorrect lower unit he has put on it? Any help or advice would be greatly appreciated.