I've got this 1969 55 evinrude that somebody gave to me a couple weeks ago. I got it running fine about 3weeks ago. I went to start it up again and it wouldn't start. I suddenly lost power to the purple wire going to the switch box. I hooked up a meter and got continuity all the way back, so the wire itself is fine. It leads to this little circular cap with one power in connecting to a circular contact and the purple to the other. For some reason purple isn't getting power. I add 12v to the green wire and shift it into neutral so the shifting is fine. When I turn the key it starts but the second I let go of the key it stops. So it will fire up and stay running as long as I keep the key turned and run the starter. (bad news I know) Could it be dirty carbs, or how do you check points to see if there ok still? Or could it still be a wiring issue? I'm getting spark on all three as well as fuel. thanks alot for your help in advance!!!