Join Date: Feb 2012
Location: Las Vegas, Nevada
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Re: MD7A Tach Sending Unit
Faster, it is actually this one: Faria, 4 In. Tachometer (4000 RPM) (Diesel) (Mechanical take-off & var ratio alt) Dress White, Model 33142.
By the looks of things, it will either work off the alternator or a mechanical (magnetic ?) pick up. The original tach was a VDO Tach and it ran off the mechanical pick up. I would prefer to keep using the same wiring from that to this new tach. I have voltage, it is just very low, or normal, if .062-.080 is normal anyway. I will have to see if the existing sender may have an adjustment for proximity to the gear or magnets.
Note my "flywheel" is actually on the front of the engine and the starter motor is up front too on the lower right front of the engine. The pick up, however, is mounted to the upper right rear of the motor as you look toward the back of the boat and is not near the flywheel, so there must be another gear with teeth back there in the engine case.
Thanks for replying and trying to help anyway. If you have any ideas, I would welcome anything.