Re: 1967 Johnson 6 HP Seahorse
The '69 manual would be a better purchase for your motor. The '65 model has the gear box from the older 5.5hp motors. It has a spring relief assembly located below the water pump plate, that the newer motors don't have. The prop shaft is also different on the '65. Once again, it is the one from the 5.5hp motors, with both the cotter key and shear pin at the outer end of the shaft.
If you find a manual of any year that has the newer gearbox assembly and the magneto ignition with the coils under the flywheel, you should be ok.
Don't pay $83 for a manual - you can get one much cheaper. I bought mine on EBay for about fifteen bucks with shipping. You can also go to
www.shop.evinrude.com for a parts "explosion" and part number list. Their info goes back to 1968, which is close enought for your purposes.