I have a 1980 Mercury 7.5 and it has I guess they call it shallow drive. Well I left a friend borrow it and he said it would rev up fine but the prop didn't spin that fast. Is that the shallow drive? Also I noticed there's a small diameter rod coming up from the lower unit with a ball on the top. Looks like this ball belongs in somewhere. It's just hanging there. Could any of this be the problem? Said it ran great, but didn't move fast at all. Like he was trolling.
