Mercury Tach hookup

catman48

Cadet
Joined
Mar 11, 2007
Messages
18
Can I attach the tach to my 04 9.9 4-stroke bigfoot? There are 3 wires from tach ,1 brown, 1 black ,and one purple, I have a OEM mercury service manual but don't see anything in there for it.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,790
Re: Mercury Tach hookup

You need 12v, ground, and a tach signal. Additionally you may have an extra wire for separate back lighting for night use.

Black is usually a ground wire. The purple may be the tach signal.....mine is gray. The brown maybe 12v but voltage is usually red.

You can use a voltmeter to determine which is which . The tach signal should be a few volts when the egine is running.

Mark
 

ricksrster

Commander
Joined
Jun 19, 2005
Messages
2,022
Re: Mercury Tach hookup

Brown signal from rectifier.Purple 12+ from ign. Black ground. See your other post in Mercury section.
 
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