I have a 1998 Evinrude FICHT lower unit from a 175 hp. I bought the unit and it was drained of oil, but what was left looked ok. When I pressure tested it, I could hear it seaping if I put my ear to the vent holes that are in the middle area of the lower unit. Also, I noticed that when I accidently bumped into the shift shaft more air would seap out. So if I rock the shift shaft air leaks fairly easily. Anyway, I went ahead and tested with the 7 pounds of pressure that it would still hold. After 3 tests at 45 minutes each, the unit still holds about 2 lbs of pressure. Any thoughts on if this is seriously abnormal; and what could cause this. Should I have all of the seals replaced? Any thoughts would be very helpful. Thank you in advance!