1971 60hp Evinrude backfires like a cannon...help please!

[dfrants]

I just picked up a 1971 60hp Evinrude. When you turn the key, it turns over, fires and backfires like cannon going off. I didn't have the prop nut on and it blew the prop across the drive way. It has what looks to be a newer CDI box, coil, and trigger/stator. The spark plug wires are not crossed, but i'm not sure if the CDI wires are connected correctly. It is a Motorola/Delta 113-7123 model with a red, blue, black, and black/white wires. The blue wire has a warning sticker on it, so i'm wondering about that one. Does anyone how these wires are suppose to be connected? Please help. Don

 

[sailfish-steve]

Re: 1971 60hp Evinrude backfires like a cannon...help please!

Sounds like timing. How's your flywheel key?

 

[F_R]

Re: 1971 60hp Evinrude backfires like a cannon...help please!

The required connections are from the key switch, ground, coil, and breaker plate. Knowing that, the only sensible colors would be are red-ignition on, black-ground, blue-coil, black/white-breaker plate.

Your motor is firing out of time. Spark plug wires would be most likely cause, but you say they are right. That leaves a problem in the distributor. Cap could be cracked or carbon tracked. Same for the rotor. Breaker points could be way out of gap spec. Should be .009" (.010" new). A very high resistance in a plug wire could cause arcing to the adjacent one within the cap, or even through the wires (called cross-firing).