Your engine has the Motorola Magna Power I ignition from factory.
It is a belt driven CD ignition with a distributor with or without points, depending if it has electronic dist or not.
Maybe it has been converted to regular auto style battery ignition if the CD module has failed.
This system need 12VDC to ignition post at terminal strip.
A blue wire goes from I terminal at keyswitch and is hot at ON and START position.
Check out Mastertech marine web site (maxrulesdotcom), they have wiring diagrams.
