i have a 1962 merc 700 70 hp. i removed the lower unit to replace the impeller a couple weeks ago. i put it together and everything was fine. took to lake several times. i decided to replace the housing since it was glued together. so when the new parts arrived i removed the lower unit agian. replaced everything and put back together and now im stuck in forward. i have taken apart moved the shift rod around reinstalled and still stuck in forward. i have done this about 6 times and still gears arent where they sould be. can anyone help? thanks