Re: 1960 evinrude 75hp
Here's a link to parts diagrams/breakdowns for your motor:
Evinrude Starflite Magneto And Distributor Parts for 1960 75hp 50522 Outboard Motor
Your '60 75hp Starflite V4 has a magneto. The only connection to the external wiring harness required is at the Starboard side of the magneto, located right above the "break line" of the magneto/distributor cap.
When the ign switch is in the "Off" position, the magneto connection is shorted to ground and spark is killed.
With the key "On" or "Start", the magneto is not shorted to ground, and if working correctly, will spark when turned.
You can eliminate the switch & external wiring as a potential problem, by disconnecting the external wire from the magneto terminal, leaving in place the wire which goes up to the the points assy.
If you still don't have spark, you're gonna have to tear down the magneto for servicing. Most likely it's "hazed" ign points which could be cleaned/gapped and placed back into service, if they're in good-enough condition. Otherwise install a "tune-up kit" which has 2 new sets of points, condenser & points lube.
A couple of other common problem areas on these are 1) bad rotor and 2) bad ign coil.
But the most common, hands-down problem is with points and that's where I'd go first.
Not having serviced one of these before, you're definitely gonna want to order that service manual. It's a pretty basic procedure, but there are things that have to be done/adjusted/synchronized "by the book" for best results.
HTH............ed