The switch is of the momentary type (push to engage). The solenoid is a Ford part that I found in my junk box. The wire (blue connector) at the upper right is grounded to the frame, and also to the bracket that is part of the solenoid.

You can also see that I made a push-button starting method for it. It was impossible to start this thing in low temperatures, as it was just too hard to spin over. So I bought an electric start kit for about $125.00. This included a different flywheel, starter, and other parts. Anyhow, it is a breeze to start now. I connect it to a motorcycle battery or the riding mower - and push the button.