1967 40hp Johnson super seahorse question? Long to short shaft?

[56Crestliner]

Hello, I just picked up this Johnson today for my old boat. Based on my measurements it is a long shaft. What I am wondering is if I can remove the section that appears to be about a 5 inch extension housing and convert this to a short shaft? The seller threw in a parts motor, and I have a short shaft shift lever. Would I need a different driveshaft, or is there some sort of extension that makes this a long shaft?

Any help would be appreciated,
Thanks Jeremy

 

[racerone]

Remove those 2 covers.--Remove the rear exhaust cover.---Remove the lower unit.----Remove the 5 inch spacer.--Install a shorter driveshaft;----------Needs shorter water tubes.----Shorten shift rod 5 inches.--------But before you do all that you should evaluate the condition of the motor and perhaps run it.

 

[F_R]

Water tubes pull out. Cut exactly five inches off them and reinstall. Yep, you will have to replace the drive shaft. You will also need a 5 inch shorter rear bolt holding the gearcase on.

 

[56Crestliner]

Well that seems doable. I did run a compression test on it and we ran it in a barrel before I bought it. It seems like a strong motor. You're right, probably a good idea to throw it on the boat in the spring and run it a little before going to the trouble though.

So next question, the 40hp Evinrude Lark 2 that he gave me for parts is a short shaft. Would this driveshaft be compatible?

Thanks again for your help!

 

[racerone]

Likely the same and the parts you need for this simple conversion.

 

[oldboat1]

If both are mechanical, may be able to just switch out gear cases. When ready, would probably drop both l.u.'s and check compatibility. Driveshaft splines must be a match. If the switch works, save the Johnson longshaft lower unit for future use or to sell with the motor.