I have a 1978 Mecury 200 V-6 that gave it up on Friday the 13th. I was under power just starting to plane out and heard a loud clunk, then the motor reved and the prop quit turning. I am new at this game but figure I have the opportunity to learn to rebuild a lower unit. Any advice or suggestions before I take the plunge? The gear case oil is good and I have not taken it apart yet, figured I would do a little research.<br />Thanks<br /><br />I forgot to mention that when I powered down the prop engaged again. I had to try one more time and the same thing happened again. That's when it went back on the trailer.