I have a 1967 9.5 hp Johnson. Starts up good. Pushes the boat fine until I get the throttle turned to about half way. Then it seems like it slips, boat slows down, and the engine revs up really high. If I turn the throttle back down below half way, it picks back up again and drives fine. I haven't worked on boat motors much, but it obviously seems like some sort of gear issue. I drained the lower unit oil, and it had what looked like a tiny bit of dirt, and looks like it may be a TINY bit milky. I can only see the little milkyness if I pour the oil from one container into another, and it shows up just as the container is emptying out.
I was about to pull the lower unit off to expose the gear case, but the screws are VERY tight (most likely lock tightened). Before I pulled it off, I wanted to make sure it's not difficult to get back on. And also get verification that that's where my problem is.
I was about to pull the lower unit off to expose the gear case, but the screws are VERY tight (most likely lock tightened). Before I pulled it off, I wanted to make sure it's not difficult to get back on. And also get verification that that's where my problem is.
