Took my 1977 24' searay out on lake powell this weekend, had been cruising fine for about 10 minutes when suddenly the rpm shot up without warning, I dropped down to idle and still had some drive, this lasted about 5 minutes when I lost all drive and had to be towed. forward/reverse neutral cable seems to be reaching the drive fine but the prop is definatly not getting any drive whether I select forward reverse or neutral - any ideas?<br /><br />Not sure if it is of any use, but here is a photo of the drive: http://oak.ucc.nau.edu/gn/drive.jpg