When you say full of water. How much? A Qt. or a little. I have seen the shift shaft seal leak after setting for a cold winter and leak lower unit oil out of the small holes in the front of the lower unit when trimmed up.. If you trim the lower unit all the way down you should have some leakage around the prop shaft seal, checking after prop removal. If no leakage there start with the water pump base plate, thinking the water pump impeller and base plate seal has not been recently changed or could be shift shaft seal. Shift shaft seal might seal off after use. Dont think the worst before checking the obvious. Hope this helps.Last edited by tschooler1956 on March 21st, 2010, 11:38 pm, edited 1 time in total.