The 1/16 inch diameter flow control orfice is at about the level of the input fitting on the side of the filter housing, a couple of inches below the top. If the canister is draining below that level, you've probably got a hole rusted into the standpipe near the bottom. That will also cause a loss of oil flow to the engine if the hole is big enough. Try removing the filter canister, clean it up, and fill it with a lightweight solvent like mineral spirits or Diesel fuel to look for the leak. It should not drain below the level of the flow control hole.
Jerry
