I believe that 'BCD' stands for Battery, Coil, Distributor. You have a battery powered ignition system much like a car on that motor, rather than a magneto type. There is a power / pulse distributor under the flywheel and breaker points. That year only the 100 horse was breakerless. Your V4 motor, being a 1968 65-horse, should also use surface-gap plugs.
Since you don't have a tach, I interpret Faztbullet's response to be that it could also be a bad coil sending an impulse back to the pulse pack.
Checking the BRP site it appears that the actual power / pulse distributor is no longer available, nor is the coil or the amplifier. The nerve, after 49 years....
Because those parts are obsolete then iBoats and / or BRP won't carry them. If you really need to get any of those parts, try Laing's Outboard Parts to see what used parts they may have. Assuming you want to 'throw' parts at it. Before that though, lets see if anyone else here has a suggestion.