recently had a repair done on my lwr. unit.(2004 mercruiser,4.3mpi,alpha one)boat has not been started in approx.2-3mos.decided to start it up before going fishing this week-end. when i connected the muffs to the inlets i noticed no water coming from the outlet where it normally flows from. i started the motor and let it run a good 10 mins.and still no water coming out the back. could i have put the gear housing together wrong?or is this a water circulating pump problem? could i have done some serious damage,letting it run? i shut it down as soon as the temp gauge started to move. thanks for any help.