What is in the CDI (switch) box?

[Medvind]

I have an Mercury 7.5 and suspect that I have an faulty CDI box. Is there anyway to test it?

I am surprised that there is only one triggersensor. How does it know which cylinder to fire?

I have sparks on both plugs. Can the CDI box break so that teh timing is wrong?

Does anyone have circuit diagram for a CDI box?

 

[duff]

Re: What is in the CDI (switch) box?

chances are that if you have spark on both cyl. the switch box is fine. i have not been able to find a diagram for mine that went bad and i lost spark on 3 of 4 cyl. good luck not 100% sure about the 7.5 horse mine is 80 hp.