70's model Mercury 402 40 hp questions

[rslack29]

I just got this boat & motor last week and I've never fooled with a motor this old before. Probably some dumb questions here, but would appreciate any help.

- What is the black switch on the front left bottom of the motor? It flips back and forth and I can see something moving up and down inside the motor when I flip it.

- I dont have a key for this thing. Is there any way to hotwire it? I have the wiring schematic...just need to know which wires to touch and where.

- What should the gas/oil mixture be?

Thanks!!

 

[badger111]

Re: 70's model Mercury 402 40 hp questions

I can't see the black switch you mention. Can you post another picture of it?
As for hotwiring it (I like your style) - It's usually the yellow or yellow and red wire to a live feed - to check, look for the starter solenoid, there'll be 4 wires, two large and two small - whatever the color of the SMALL non-ground wire, that's the one to supply a live feed to (only until it starts!!) - or you can use the pull-start!!
The mixture for that is 50:1

 

[rslack29]

Re: 70's model Mercury 402 40 hp questions

I can't find a picture of it...that's not even my motor; just one like it. I think I may have figured that out. I think it is the stop switch. It is a flat vertical switch. I think it's #23 on this first diagram.

There are 3 small wires on the starter solenoid (yellow, black & red).

 

[badger111]

Re: 70's model Mercury 402 40 hp questions

If you want to start it from the control box without the key you'll need to cut the wires off of the back of the switch. Join the red and white together and then touch the yellow wire on them to start. To stop touch the black and salmon together. (look at "Key Switch" section on that diagram and follow what wire combinations you need to run, start and stop)