1963 40 horse johnson jolts

[DanLieffring]

I have a 63' Johnson 40 horse super sea horse. It runs great, but have 2 issues.

When it's running, the motor jolts like I hit a stump or something. I'm guessing it's slipping out of gear for a second. It happens randomly. Any idea what might be causing this?

Also wondering about the cooling system and replacing the impeller and/or water pump. I don't have any issues, but I've had the boat for 20+ years and done nothing. What should I look to replace, and is there a kit?

Any advise would be great.

 

[itstippy]

Re: 1963 40 horse johnson jolts

Usually "jolting like you hit a stump" is a worn clutch dog slipping on the forward gear cogs. BUT . . . Is your '63 SuperSeahorse an electric shift? If so I suspect a bad wire intermittantly shorting/grounding out and causing the forward electromagnet to engage/release/engage. Which type of shift to you have?

 

[R.Johnson]

Re: 1963 40 horse johnson jolts

You can jumper wire to the forward gear. That take's all wiring , and switch's out of the problem. If it still jump's out of gear, you have a clutch spring problem, or you could have a prop hub that is slipping, not uncommon on that age engine, either one. Mark the prop on the inner hub with a magic marker. When the engine slip's, check the marker on the hub, if in alignment, you have a gearcase problem. Spring, and gear hub wear. Still, not uncommon if water has got into the gearcase.

 

[Fl_Richard]

Re: 1963 40 horse johnson jolts

Yea, all that and change your lower lube and install a new impeller!

 

[F_R]

Re: 1963 40 horse johnson jolts

Asuming mechanical shift, "jumping like running over a stump" is a worn out clutch dog and forward gear in the lower unit. Happens every day somewhere. If you don't fix it you will have more problems when it beats the shift linkage to pieces.

 

[DanLieffring]

Re: 1963 40 horse johnson jolts

It's a mechanical shifter. Not Electric.

Thanks for the replies