I found this thread while researching my problem with my 1989 alpha one. I am new to boating and know very little about the i/o but i do have a bit of automotive experiance. To my problem, this weekend my boat developed a, and i apologize for the vague description, thud that you could hear and feel anywhere in the boat. We think we traced it back to the lower unit. The thud did not seem to keep pace with the rpms but the did increase in speed when the boat did, but again not in timing with the rpms. No vibrations or anything like that just a dull thud we could hear and feel. At the same time we noticed that when in reverse the boat did not respond as it did in the past. We could throttle up in reverse and not go backwards very fast at all. Is sounded like something was grinding and or slipping like when either gears or teeth are wearing out. We beached the boat and checked out the prop. We could turn the prop one way with a ratcheting type sound and feel to it, but we couldn't turn it the other way for the most part, in forward for every 15-20 clicks and positive stops, it would slip and go backwards, but in reverse we nevergot it to slip backwards. So thanks to my research i was wondering if this sounded like something to do with the reverse gear, or the clutch dog, or something completely different. As i said i am new to this so if i left out any crucial information the would help you to help me diagnos this problem, please feel free to ask and i will answer it to the best of my ability. Thanks in advance for any help you can give
