I have green box single handle control for my Mark 78A, it has the 2 switches in it with 3 post on each switch, I understand the switches, and have rewired them, and have a new 3 pos. ignition switch, the old one has 4 positions, My confusion is if the chrome button on top is used to start and choke the engine, what does the 3th position of the ignition switch do?? Nothing? seems it is not used. Just turn on the switch and then use the button to both choke and start the engine? Also since the new ignition switch has only 3 contacts, I assume that I run all black wires together on the pilot light to eliminate the 4th position on the switch. I have the wiring diagram but it can be confusing. Thanks for any help. Rick