73 115hp johnson diagrams

bansheetaz

Cadet
Joined
Dec 1, 2005
Messages
20
is there anywhere i can acquire a wiring diagram for a 73 115 hp johnson? im trying to hookup a tach guage (OMC). it has 4 wires coming out of the gauge gray, purple, dark blue, and black. the dark blue is power for the backlight and the black provides a ground for the light but im unsure of where the gray and the purple wires go. any help would be greatly appreciated. also im trying to figure out how to hook in the warning beeper for overheating. thanks<br />troy
 

OBJ

Supreme Mariner
Joined
Dec 27, 2002
Messages
10,161
Re: 73 115hp johnson diagrams

Welcome to iboats Troy!<br /><br />The purple goes to any 12V source...usually it's connected to the ignition switch to power up the tach when the key is turned on. <br /><br />The gray wire is the pulse or signal wire. You should find a corresponding wire in the wire harness from the engine.<br /><br />Usually, there is a plug provided on the control box to allow you to connect the tach. It's located below the key switch...near the bottom of the control. BRP makes a harness which has the mating plug and leads that go to the tach. You can also find this lead (I believe) in iboats mega mall.<br /><br />EDIT: Should have mentioned that the connector on the control box didn't come around till around 1979 with the new designed control box. If you do have the newer controls, the PN for the tach lead is 174732. 'Bout $16 American.
 

Indymike

Petty Officer 1st Class
Joined
Aug 17, 2004
Messages
364
Re: 73 115hp johnson diagrams

Unless it's been removed the hot horn is already installed and connected in your control box. It's wired to purple and tan wires. Purple comes off of ignition switch and tan comes from sensor on starboard head. You can test the horn by turning ignition switch to on and grounding the tan wire at the engine.
 
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