Tach Wiring diagram

Thuddie - That link opens fine for me but it's for Mercruiser I/O or I/B's, not OMC O/B.

Are you just trying to figure out which color harness wires go where on the tach ( Black- G terminal (ground), Purple- B or "12V+" ( from the A terminal on the ign sw. I think, Gray -S or "PUL" terminal [ tach sender terminal to a terminal strip on the engine , and probably specifically to the terminal with a yellow/gray wire to the engine [stator & rectifier??) ],... maybe ....even a light Blue on tach terminal next to the bulb's rubber cover at back-top , to power the backlight from a dash lighting circuit daisy-chain ?

Disclaimer: those suggestions are taken from an '80 Johnson v-6 diagram and it doesn't show the tach itself , just engine to the plug .

A quick search for "OMC tach wiring" has one of the links on another forum showing the back of the OMC outboard tach with no wires attached.

A quick search came up with this site for covered '76 85hp manual download, but I didn't try to download it & have no idea if it is legit and free or what :
http://www.repair-guidebook.com/ind...3-1984-1985-1986-1987-1988-1989-pdf-download/
 
Your a good un' Sandy.
I think I have it now. From another guy I found out the Brown wire from the Tach should be connected to the Yellow wire from the Stator. The low output side if I have two.

What I really wanted to do was invent a Tach for the Magneto Ign of the older small Hp models.
Something to pick up the Magnet in the flywheel as it passes, make a pulse and see that on the Needle of the Tach.

Anybody know anything about that?
 
Plus a lot of diesel tachs have a magnetic pickup option so that type pickup doesn't rely on a stator.

I have a h/h optical tach too that reads the rpm of a white mark on any revolving item.
 
Yup, I knew about TT, and there's a version that's wireless. You can keep it in your shirt pocket.

I wanted to make an Analog Tach. I guess I was just dreaming out loud though.

I was gonna take the pulse off the Flywheel magnet as it went by.
Then I found one for a Diesel that would work too. It's Optic and counts the Black & White stripes you paint on the Flywheel.
I never found anything 'easy' that I could make from stuff in my Barn.
I'll get it done though. Without buying a ready made unit. Now that's true to the Heart of stubbornness eh?
 
That guy did a great job making a 'chumk' for his inductor. I was just going to use the Field from the Ign Magnets.
I saw another Pully that size with Four equal Painted parts, two Black and two White, for the optical pickup.
 
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