Rebuilt a 1980 351W last year in a MasterCraft, with some of the upgrades to the motor I found it easier towards to end of the rebuild to install an electric pump rather than tear the motor back apart to maintain mechanical pump. 13 months after getting everything mechanically and electrically done and now...

The pump is leaking from a small hole on the pump side just below a brass plug that is pushed in. Why is this leak happening, where is it coming from, and what (if anything) can be done to fix it?