Only Cub Cadets - CH25S MDI tach?

Only Cub Cadets (https://www.onlycubcadets.net/forum/index.php)

- Kohler Engines (https://www.onlycubcadets.net/forum/forumdisplay.php?f=50)

- - CH25S MDI tach? (https://www.onlycubcadets.net/forum/showthread.php?t=53906)

Quote:

Originally Posted by RAC65 (Post 472350)

Yeah, tried the inductive pick-up, no dice. Had a MSD GMR pick-up that I think does pull a signal from the cut-out wire but the output signal from the GMR unit isn't high enough voltage to drive the tach. The tach will run from a dummy ignition using a early 4 pin GM HEI ignition and coil with a Chrysler pick-up. but the coil has to be in the circuit to run the tach, the signal from the 4 pin HEI on its own won't run this tach.
Never tried it, but what about pulling signal from stator wire going to rectifier/regulator?

You'll get a roughly 50VAC signal if I recall correctly. I dont' think you could run a tach on that.

If you can divide the reading down, the one stator lead to the voltage regulator has about 40 volts.

Quote:

Originally Posted by cooperino (Post 472353)

I think the CD system is what he is trying to achieve. I would be looking into inductive CD tachometers

The desire is to run the factory tach installed in the dash of the tractor. The signal it wants is most similar to a points ignition/early auto electronic ignition. Why Kohler chose to provide that type of output from the SAM modules on the CH series twins is a mystery (perhaps just a coincidence). It seemed to me I saw a post here at OCC where a owner was running a tach that way on a diesel cub.
The dummy set-up was just a test unit to make sure the tach wasn't the issue, then I thought well I'd just put a pick-up nub on the spacer behind the electric PTO and use a auto distributor pick-up and a GM 4 pin HEI to convert the signal (both cheap parts), but that signal isn't a high enough output voltage for this tach without the coil in the circuit (feedback from the neg. pole on the coil provided the voltage spike necessary to run the tach), don't want an extra coil just hanging around under the hood. Has to be a more "elegant" solution.

Would an abs wheel sensor,
provide a signal for the tach?(picking up the impulse from the flywheel magnet)
Or if you ran the sensor through an early GM HEI for amplification?
Another thought,
an early "points eliminator" from Briggs, as a trigger?
---just thinking here :bigthink:

What does your original tach look like? Maybe theres one out there that will fit in the stock location but function with the wire wrap method?

I saw this one. It looks similar to some of the stock kohler ones i have seen

Edit.

Correct link
https://www.amazon.com/Maintenance-T...ur+meter&psc=1

Being it is a Simplicity, its prolly a Legacy and has an instrument cluster.

Quote:

Originally Posted by darkminion_17 (Post 472380)

Being it is a Simplicity, its prolly a Legacy and has an instrument cluster.

BINGO! Keep in mind the tach is fine and worked fine with the SAM ignition. It's the Kohler replacement MDI ignition that's the issue.
If I could just figure out who manufactured the tach I might be able to better assess options, but the cluster comes as , well... a cluster.

Maybe Simplicity has an upgrade for this issue besides replacing the cluster for 600.00

Here is a guy selling a set of coils on FB. https://www.facebook.com/profile.php?id=100011472189840

I googled the part number and it mentions a speed sensor. https://www.kohler-engine-parts.opee...oducts_id=6577