TOPIC: 1967 Mercury 500 Question

I’ve got a 1967 Mercury 500. It needed a foot. I had a guy retro fit a Big Foot LU and get the motor running. He just jumped the starter to crank it with a screwdriver. He had the motor running. It fired up in half a turn. I didn’t take the boat home that day. I picked it up a few days later. We didn’t fire it up that day. I let another guy that owed me money install 3 position push to start key switch that he said he had. When I got there He couldn’t find it. He sent me to go pick one up. I got back. He wired it up wrong and smoked the internal harness. I started looking up wiring diagrams to insure where the wires were was correct. I couldn’t find a diagram that matched what I have. There is no switch box, no magneto under the fly wheel, no rectifier, that I can identify, and no mercury switch.
Were there any 67’ model 500’s that came this way. Could the motor have run without these items? Hell can a Bigfoot LU be retrofitted to a 500? These guys are related. Now the one who smoked the engine says it just needs new points and condenser. However, he has a 60hp Johnson with electric trim and runs great for $600. He said the motor was a POS and he’d get the Johnson and part out the Merc. I’m wondering if they robbed items off my motor. Maybe they didn’t. Maybe Mercury had an electric start without these items. If not would a certified Mercury Mechanic know this right away?
Let me know.
I may take them Gator Hunting. Bad things can happen in the Delta but it’s fun. You can’t put a price on a good time.
Thank you in advance.