Often the quick disconnect on those engines goes bad. If you wanted to rewire it like OEM, you would need a suitable waterproof plug with two battery cables and about 7 other wires, that fit or almost fit the quick disconnector hole in the lower cowling.
The other choice would be to use marine bullet connectors for the small wires and run the battery cables from battery thru the hole in the lower cowl to the starter solenoid and ground. It would be ugly but would work.
