1973 Evinrude 40 hp

Hello all, not sure if this is the right forum. I recently bought a boat that has a remote-steering 40 hp Evinrude, think it's the "Big Twin" 1973 model.

Over the next few months I will be doing some serious cosmetic work to the old Smoker Craft aluminum boat.

I need to disconnect the motor from the steering cable, controls, etc. to take the motor off the transom. I have never done this before as I've always had a little jon boat with a tiller outboard.

Any advice on how to do this?

Also, I will probably be selling the Evinrude. I have a buddy who might sell me a much newer model (mid-90s) Yamaha 40 hp to put on.

Question - will i need to replace the steering controls, throttle controls, etc? I assume I can't just swap out the motors since they are different brands and much different ages.

Thanks for any info.