1979 Mariner 90hp Wiring Harness to Engine

[rcwannab]

Recently acquired a project boat with 90 hp Mariner inline 6 SN# 5310112.
The plugs have been cut from both the control box wire harness and the engine harness.
It think I have most of the wires figured out in order to hard wire the control box to engine, but have a single white wire form the control box that I can not determine where it should go in the engine???

 

[wrench 3]

You don't need the white wire for your engine. It's an ignition feed (12v) for a battery powered ignition system. Yours is a magneto type system that has it's own generator (so to speak).

 

[rcwannab]

Thank you for the response. Unfortunately i tried the ignition key and nothing. Looks like previous owner did some major rewiring replacement in the engine. Service manual should arrive tomorrow so I can start tracing the issue.

 

[wrench 3]

Good luck

 

[rcwannab]

A lot time spent tracing and replacing wires. As best I can tell, there are no wire leads from the starting battery to supply power for ignition. Is there supposed to be power and ground wires from battery that would have went to the harness connectors?

 

[rcwannab]

Here is pic of temporary wire collection from control box (left) to engine (right)




Just not sure how power is supplied from battery

 

[Chris1956]

1979 was the changeover from battery-powered CDI igntiion (single coil w/ distributor) to the more modern ADI (6 coils, alternator driven Ignition and no distributor) on the Merc/Mariner Inline sixes. The white wire from the ign switch was used to power the battery powered CDI igntion. It was not used in the ADI. The orange (or salmon) wire was used to ground (or kill) the ADI ignition power, and was unused on the battery-powered CDI.

New harnesses for the engine are available in several places. They usually have both the white and orange wires and therefore fit both types of ignition. Boat harnesses are a bit more expensive and hard to find.

 

[wrench 3]

The red wire is the feed (12v+) to the key switch. It comes from the battery side of the starter solenoid. It splits in the engine harness with on end going to the rectifier and the other to the main harness connector. The black at the harness connector is grounded to the engine with a split going to one of the small terminals on the starter solenoid

 

[rcwannab]

Thank you for the info. I will put this info to use over the weekend as I try to keep chipping away at all the issues this project has. I got this as a project after seeing how much assistance this forum can provide in order to learn . Thank you for the assistance.