1976 Johnson 35 jumping?

I recently got a boat, the guy said that it was jumping when put into gear, i didnt worry bout this much because i thought i knew what it was, well got out on the lake and it went good first two or three times but really was jumping quite a bit, I got my father out there with me and hit it wide open, went good, but was still jumping then it came outa gear, engine revved as high as i have ever heard then kicked into gear, snapped motor mounts, knocked hole in boat, never seen a motor jump out of the water so high, then motor sank. We got the motor back up in the boat and was towed in, took it apart almost immediatly after getting home,
I figured the forward gear was getting the ears rounded out, turns out that the forward gear is like brand new? as a matter of a fact all three gears are like that, He said he replaced one of them , but I was unable to tell which one as none of them had any signs of wear. everythng looked good? so i put it back together, welded up mounts, went back to the lake, still same thing, any ideas? the shift cable is ajusted correctly too, checked that b4 I bought it.

Re: 1976 Johnson 35 jumping?

Shift cable may be adjusted correctly but not the engine shift system.
On attached pic:


Loosen the screw in the slot on shaft #39, and be sure the gear case is in neutral.
Adjust the lever so it is even in the neutral mark on the arm on the side of the block, tighten the screw.
With shift cable disconnected, take a test drive and shift with the lever only.
If ok, re-adjust the shift cable and do another test run.
If still not OK, check the shift cable travel.

Re: 1976 Johnson 35 jumping?

resize your diagram.

Re: 1976 Johnson 35 jumping?

Did you test for a spun propeller?

Did you check the shift rod connector between the two shift rod sections to be sure that the screws have a firm grip on the rod? You have to completely remove the screws to do this correctly.

Re: 1976 Johnson 35 jumping?

I assume you mean by a spun propeller, it would be stripped? The Prop is new, the previous owner replaced it, he said that helped, but it still done it. I have checked the shift rod linkage, where they come together anyway, I am going to check the number 39, tomorrow, Thanks for the help everyone.