Tachometer wiring?

mike8282

Cadet
Joined
Apr 27, 2010
Messages
16
I'm trying to wire a tachometer to my 86 Johnson 90 hp. If anyone could tell what wires from the outboard do I attach the wires from the tachometer?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Tachometer wiring?

There are four wires on a tach -- only one of them comes from the engine. The wires are as follows:

L = internal light connection -- connects to the light terminal on any other gauge or to the NAV side of the navigation light switch.

Ground = ground -- connects to the ground terminal on any other gauge or the ground lead in the engine harness.

+12 Volts = This connection is labeled "I" on most tachs and is connected to the "I" (+12 volt) terminal on any other gauge or the "A" (accessory) terminal on the ignition switch.

S = Send terminal -- Connects to the TACH signal from the engine harness. Depending on the year of the engine, there will be a three terminal plug below the ignitiion key on the control box. +12 volts, ground and S (send) are available there via an optional tach harness (available from the dealer or possibly here on IBoats).
 

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: Tachometer wiring?

The gray wire in your control box is the pulse feed for the tach.
 
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