My father in-law gave my wife and I his boat, before winter he drained the lower gear case oil. Don't think he had done it before or had been a long time. He removed the screw just above the very bottom that you should to drain the oil. Its listed as screw 55 in the manual's I can find. The problem now is it won't re-screw or get tight. I'm assuming it should be tight else it would vibrate out. Is there anyway to get this tight without dropping the lower unit. From what I've read its either the alignment of the two parts the screw goes into or its stripped. Assuming its the alignment is there anyway to get it tight without major work?