If you have a desktop computor, follow this link to a manual put out by CDi electronic
https://www.marineengine.com/parts/cdi-electronics-outboard-parts/outboard-ignition-troubleshooting/
Start on page 28
You have 1 wire going from the points to the cd box, but there is another wire coming out from under the cap that makes a ground for the breaker plate. check to see it the breaker plate has a good ground. Load test the ground with a halogen headlight bulb hooked to B+
Here's some things to consider!
You cleaned the points, but didn't replace them. I believe the points are tungsten and you really don't know how many times they have been filed or ground on and sprayed with what ever. To get all cylinders to fire you need both points operate correctly. I would...
When i found the wires leaking on my 1969 85hp, it was a very very thin white arc, not a bright blue arc.
i know you said you replaced the wires, but were they 50yr old old stock parts?
I made new wires using new Belden solid core 7mm non resistor wire.
Another idea is if he doesn't want to run another wire, We (auto mechanic) would take a halogen headlight bulb to load test the circuit. Very bright light=good amp carrying capacity
Also check the continuity of the wire for the points that travels up to the breaker plate. pay close attention were the wire is clamped to the breaker plate.
I am assuming you have a good multimeter!
Take your flywheel off once again and put the nut back on the threads so you can turn the crankshaft. unplug the wire going from point to the cd box. Hook a multimeter set to ohms to that wire and then to a ground point on the engine. turn the crankshaft and observe the ohm reading on both sets...
You said you put new wires on it!!!
But did you install new boots at the dist cap? I replaced my wires but not the boots, and the results were exactly the same as what you got now. I had to install new boots and pack them full of silicone dielectric.
You stated you had black arcing type spots...
I would pack your spark plug wire boots were they attach to the dist cap with silicone dielectric grease before you spend anymore money!
Your symptoms match what i had to a tee of what i had on my 1969 85hp
