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Mercury outboard; wiring 2003, 90HP to a 1979 90hp control

Capt. Bob

New member
I just purchased a 2003, 90hp Merc outboard (serial no. OT699512). I am replacing a 1979, 90hp Merc (serial no. 5160490) on my houseboat. I also have the male connector with an attached pigtail. I could use some advice on hooking this thing up. Thank you in advance, Bob R.
 
Thank you very much. That Merc wiring diagram is much better than the one I had and the chart clears up a lot of my questions. I got a new style pigtail with the motor so I just have to purchase the plug assembly for the boat end. I still have to work out how to tie in the start and neutral start circuits but I'm well on the way. Thanks again. Bob R.
 
Here's what I got; maybe you could correct me if necessary: new purple to old white, new black/yellow to old orange, new yellow/red to old yellow, new yellow/black to old gray, new gray to old brown and new tan to new horn. Thanks again for your help, Bob R.
 
New purple to old white = 12v,new black/yellow to old orange = kill circuit,new yellow/red to old yellow = starter circuit,new yellow/black to old gray = choke,new gray to old brown = tach signal,new tan to new horn :confused: hmm,tan is usually for temperature sender on the engine block to gauge on dash,but if you don't have a temp. sender,it can be used for whatever you wish.I use different colours but I'm the only one who works on my boat,I also tag them,just in case:D
 
Thanks for the verification. My 2003 manual shows a low oil level warning horn and it looks like the tan wire comes from the sensor (As well as from the temp sensor); I figure the horn would be a wise addition.
Thanks again, Bob
 
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