Day one hook up rabbit ear to lower unit turn on water let it run for 2-3 min. than turn key in boat,engine was a little hard to started, but I knew it would be for the first time of the year.So she started right up I ran it for about 15min.The next was father day my son whatto go swiming So off to the lake. Got the boat off trailer in the water try lower the lower unit wouldnt go down try it again same problem. Got boat out of the water check the trim/tilt to made sure she had fuild add a little. had touse the manual release to get unit down. Than press switch the unit raise up. Ok back in the water but still had to use the manual screw to get unit down. Start engine sat for a 1-2 mins back out of ramp and off we went. Than I started smeel something like it was burning turn around smoke was coming out of the back turn engine off got the fire extingusher spray the engine down got the family off the boat. The good thing was there was no flames. pull boat out of water when home pull cover off engine hose her down spray so engine cleaner on her didnt see any fire damge good.But I did notice the manifold had a hair line crack in it. So I hook the water back up started the engine and water was coming out of the crack. I cant figure out why the lower unt will not go down but will raise and I guess being the manifold had the hair line crack she over heated. Any help is welcome.
What kind of engine and outdrive? How old, etc.