# Outboard Tach?



## Brett (Jul 16, 2008)

Merc electric start, Jeff?

Wiring color codes for outboards to attach the tach properly.

http://www.maxrules.com/wireindex.html

Dash mounted tachs operate off the alternator output of the outboard.
The tach "counts" the pulses produced by the alternator to determine the rpm's.
Different outboards have different pulse counts so the tach has to be set to the proper spec
in order to function properly. Instructions are included with each tach.


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## HaMm3r (Dec 11, 2006)

Hey Brett, it's a Merc yes, but no electric start. I already checked the shop manual for the outboard to see if the control box had the wiring hook-up for a tach, but this one doesn't (it's normally the gray wire). So that's what led me to ask the question here.

Basically, I tink I need a tach that will read the pulses from an ignition coil, rather than the alternator. That's how the Tiny Tach works, but I'd prefer something more aesthetic.


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## Brett (Jul 16, 2008)

Only brands of inductive marine tachs I know of are SenDec and TinyTach.
Neither have the finished look I'd want.


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## HaMm3r (Dec 11, 2006)

Well, unless anyone else chimes in I'm going to call CDI Electronics tech support on Monday and ask them, since the stator and switchbox I have are both from them. Even though there is no "tach" output wire, perhaps it's possible to run a tach off one of the stator leads. I just want to make sure it won't damage anything.


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## HaMm3r (Dec 11, 2006)

Well, I called CDI this morning and got the official answer. To add a non-inductive tach to my motor, I would have to purchase an auxilliary stator and rectifier, essentially converting it to an electric start, minus the actual starter. It's not worth the $300 it would cost, so looks like it's back to the Tiny Tach for me. :


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## Brett (Jul 16, 2008)

Back when I worked on diesels, we used magnetic sensor tachs.
I think they worked by counting the passing teeth or boltheads on the flywheel.
Pretty sure they're still used....check Datcon gauges


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## HaMm3r (Dec 11, 2006)

FYi - Figured out how to do this...

http://www.microskiff.com/cgi-bin/yabb2/YaBB.pl?num=1336709969/9#9


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