I thought my problems were solved, but they are not. Motor still down on power.

To refresh memories, I replaced the old points distributors with Mallory "Ready to Run" Magnetic breakerless distributors.

Today I ran some more test. Voltage across the coil with wires hooked up and keyed on is 4 volts. When I go to positive side of coil to engine block I get 11.5 volts. But 4 volts from + side of coil and - side of coil.

Also measured the coils resistance from + side and - side and its 2.5 OHMS. The coils are original merc point style coils. Do the coils have too much resistance for electronic ignition?

I did that change once. From old merc points to Mallory MBI.

I removed an external resistor.

Maybe your boat has a "resistor wire?"

(I know that many older mercs had a resistor wire.)

I was very happy with mine. It was an SBC.

Oh yeah.... I had to buy a new coil.
Almost forgot.

It was a mallory and it was very shiny and pretty.
They sold it to me when I bought the MBI.
Same exact shape and size as my original coil.