I went to raise my engine after boat had sat all winter with the engine in near full down position. (engine is 92 115 merc outboard. trim would not move engine up or the rest of the way down. I could here the trim motor working in both directions so I assume electrical is ok. I then manually released trim per owners manual & let eng. down all the way. I then tried to trim it up again with the switch, motor ran but engine did not move. I then manually raised & lowered the engine using the over ride screw. I then checked fluid level although there were no external leaks. upon opening filler plug airated fluid. came out of fill hole, called dealer & he said I should bleed system. I tried to bleed system not really knowing what I was doing & got motor to move down with trim button but it would'nt go back up so I continued trying to bleed the system. now engine will go all the way up but will not move down. at one point engine would move all the way up but would only go about 4 inches from full down. I then backed the manual release screw all the way out & air would blow out of hole under high pressure. I assume I need to bleed the system. but obviously I'm doing somthing wrong. I don't understand how air would have gotten in there in the first place. can anyone tell me the propper procedure for bleeding the system, or am I barking up the wrong tree?<br />Thanks in advance, Chris in Spokane, Wa.