You could try unplugging the round electrical connector on the engine to isolate the engine from the boat wiring. then jumper 12 volts to the power pack and then jumper the starter solenoid to crank it. If it starts and stays running then you might have boat wiring issues
So it did start and then die and not restart1! when it won't restart, do you still have spark at the plugs? spark should jump 3/8" at the spark plugs. get yourself an adjustable spark gap tester. and get a OE service manual for your engine
If you have 3/8" spark but not start, perhaps clean carbs
I went thru this very problem with my 1969 85hp evinrude last year! The info that Crosbyman gave you is top notch. Use it to get you to the point were you get a spark at the coil that will jump a 1/2"gap.
Then i found was spark plug wires this old will need to be replaced due to leakage. I had...
Are any other mid sections and transom mounts transferable to the 1969 engine? I looked at parts diagrams and don't see anything with tilt until the 1977 models