Note that the coil is not part of the engine fuse circuit. The coil is not fused. If you don’t get a big fat spark when manual grounding and ungrounding the coil, then you may have a high resistance connection somewhere. Try a hot wire directly from the battery + to the coil + and try again...
The coil only makes a spark when the + is energized and the - side is momentarily ungrounded. Disconnect the wire at the - side and see if it makes a spark when grounded. If so, there is a problem at the - side, such as it is always grounded.