Re: 1961 10hp sport twin help please.
agreed. If it's more of an abrupt "Bang", or it feels like you hit an undewater stump, it's probably the clutch dog, if it stops pushing the boat forward , but other wise runs ok, then returns to pushing the boat again at lower throttle then it's probably sup hub. There's a very simple test you can perform to verify the spun hub. Just type in sup hub in the search box and you'll find it. Either way you'll need to get it fixed. No fun if your motor "runs", but won't "go", so to speak. I just replace the clutch dog in my '61 10hp Johnson, which is virtually identical. It wasn't hard to fix, and I got super lucky and a local mechanic gave me one he had laying around...for free! Otherwise, I was looking at about $65 for one online :/ However, you might get lucky and be able to flip the dog around so that FWD works much better, however REV may now suffer, but as it is generally used less often and at lower speed, you may be able to get away with it. However, if the tabs on both sides are worn, you'll need a new one. It doesn't take much for them to start to fail. It was about the only weak spot these old gems had, but it is 50 years old after all. IF you discover the the hub is spun you'll have to send it off to a prop shop, or take a prop off a donor motor. They may even sell new ones that will fit the prop shaft size. Search "worn clutch dog" and "spun hub" and you'll find tons of threads. Good luck.
