Mercury 20 HP Phase maker ignition 1972

[Flipperboat]

Interestingly, I am having a weird problem finding the spark in my 1972 20 HP Mercury. I pulled the external coils tested them and they are okay. I put them on one at a time and tested them individually as I put them back on the engine. Each one of them tested great and I had good spark at the plug (individually). When I connected them both I lost spark on both. Any ideas where the problem would be. Points good. No way to test the condenser. The book said check it with an ohm meter and it checked out fine but wasn't really the right test. New wires all the way around. What would make the spark go away when both are connected?

 

[Laddies]

Re: Mercury 20 HP Phase maker ignition 1972

Probably low voltage caused by a bad diode here'sa systems test