Tach install but confused on engine wiring

[pchrispy5]

I want to hook up a tach to my 1968 Mercury 650S. The brown tach signal wire doesn’t seem to bring anything up, and my outboard doesn’t have a stator or a rectifier. It was in that transition year that they had the kind of self running setup with or without a battery. I don’t know where the connection Point would be as the brown wire connects with the salmon wire in the connector, then only the salmon wire goes to the box. The box has a total of 5 connections, 6 if you include the body ground. 3 for the distributor (lightning energizer) and 2 go to the coil. Where would I hook a wire to for tach signal? I added an image of my wiring setup.

 

[faztbullet]

Tach has got to know how many poles to covert...gotta have a stator & rectifier

 

[pchrispy5]

I have the right selection on the tach for the 12 pole, just not sure where to hook up. The salmon wire on the engine side hooks up to the blue distributor wire along with the engine’s mercury switch. Not sure what the distributor wires are supposed to be for as far as what does what.

 

[faztbullet]

Tach has got to see a stator

 

[pchrispy5]

Is it possible to hook up to one of the coil wires? It is hooked up to the coil on some car/inboard setups. Could I do the same here?

 

[pchrispy5]

This is the coil. Pic 2 has the black wire on top and the white wire on bottom. Later versions had green instead of black, and black instead of white. I’m assuming my white wire is the negative. Does this coil work the same way as the 2 wire distributor coils on older cars or is the signaling different?

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[racerone]

It was clearly stated that there needs to be a ---Stator ----for that tachometer

 

[ocboat]

Mercury made a tach specifically for that engine and possibly Airguide also. They are very hard to find and there is not a lot of information about them. I owned that same motor many years ago and could never get a tach to work on it. Good luck.

 

[pchrispy5]

It does have settings for inboard motors too. Which is why I asked. If it would work off the coil like an older car or older mercruiser and just set it for an inline 4 single pulse. It the Mercury marine 6k tachometer

 

[faztbullet]

Wont work as not a 4 stroke and coil likely to burn tach up as voltage is amplified into coil. Not like a car ignition

 

[pchrispy5]

So I wanted to provide an update. I did find something I could use to send a tach signal. It is a controller that picks up the tach signal through an induction wire, then sends it at as a 3 wire rig going up to the tach. Now have access to my tach up at the dash. Just wanted to update for anyone looking at the same issue I had.