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No Tach After Replacing Stator and Trigger - Tach broken or on wrong setting?

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  • No Tach After Replacing Stator and Trigger - Tach broken or on wrong setting?

    As mentioned in an ongoing post, I recently replaced both my trigger and stator on 1984 75Hp Mercury outboard. I get spark on all four now but now my tach doesn't work. New stator is from CDI, old was original Merc.
    I have two questions:
    1) Can I run a long wire from my rectifier up to the tach to test? (Should I try that?)
    2) I saw somewhere that different stators have different settings and that I MAY need to change something on the back of my tachometer. Help me with this guys.
    Thanks in advance!

  • Texasmark
    replied
    The rectifier gets sine waves from the 6 coils of the stator on the two yellow wires. The rectifier/regulator rectifies these AC sine waves into + DC pulses and sends a sample to the tach (grey wire) and send the main power to the regulator within the module. The regulated DC output of the module are the red wires, the large red wire connecting to the same terminal as the battery cable on the starting solenoid. The rectifier and the battery - are referenced to the same point....the engine block.

    To run a DC motor backwards you have to reverse the polarity of the DC voltage applied to it. The starter is fed + voltage from the output ⅜" copper terminal of the starting solenoid while the ground return is the black wire connecting between the engine block and the starter case.

    The starting solenoid input ⅜" input copper terminal is usually used as a 12v distribution point since it's there and has ample current and is where the battery + terminal is connected. For power to move through the solenoid in either direction it must be energized by the control winding....no current through the control winding....aka ignition switch not in START position and no accidental shorts across the big terminals and no power will move through the switch...in either direction!

    If you don't close the solenoid contacts and jumper right across your starter proper meaning you's have to get the battery - terminal connected to the red starter lead, and the battery + terminal to the black lead, the battery current has no way to get back to any components of the engine proper.......and you would have to disconnect the battery from the engine proper to accomplish the reversal.

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  • TomsSearay
    replied
    Thanks for the reply. Hum...When I disconnected the remote switch and used the ignition key, the starter engaged and turned the motor over. I was trying to run the motor on muffs but didn't get a flow through the pee hole so I shut it down. When using the remote switch, the starter gear spun down instead of up so I thought it was going backwards. Apparently, not. Shame of it is, I just replaced the regulator/rectifier because the tach wasn't working. I will go through it again.

    Leave a comment:


  • jimmbo
    replied
    Originally posted by TomsSearay View Post
    On a similar note, I attempted to start my motor ( 2000, 115hp 2+2) with a remote starter switch and hooked it up to the top and bottom poles on the solenoid. The starter spun; but, in reverse. Did I damage the rectifier?.

    Hooking up a Remote Starter Switch to the Solenoid incorrectly won't cause a Starter Motor to spin backwards. Hooking a Battery up backwards might cause that, and it 99.999999% guarantees a Damaged Rectifier

    Leave a comment:


  • TomsSearay
    replied
    On a similar note, I attempted to start my motor ( 2000, 115hp 2+2) with a remote starter switch and hooked it up to the top and bottom poles on the solenoid. The starter spun; but, in reverse. Did I damage the rectifier?? What would be the test for damage with an ohmmeter? TIA.

    Leave a comment:


  • comstox
    replied
    Originally posted by jimmbo View Post
    It guarantees a blown rectifier
    POP goes the weasel?

    Leave a comment:


  • jimmbo
    replied
    It guarantees a blown rectifier

    Leave a comment:


  • comstox
    replied
    Originally posted by jimmbo View Post
    Rectifiers can test fine on a DVM, or multimeter, but when under higher Voltage and Current, not be fine
    I think this is what I was experiencing Jimmbo. And I'm not sure if you had read an earlier post where I had accidentally, (I'm still not quite sure how,) had hooked up my battery terminals the wrong way! THAT may have also attributed to the bad rectifier.

    Leave a comment:


  • jimmbo
    replied
    Rectifiers can test fine on a DVM, or multimeter, but when under higher Voltage and Current, not be fine

    Leave a comment:


  • comstox
    replied
    Originally posted by jimmbo View Post
    Does the Stator look the same as the Original, as in same number of coils?
    Yes Jim. Same.

    I HAVE AN UPDATE!!! - Even thought my current rectifier tested good, I ordered a new rectifier anyways, and guess what???? MY TACH IS BACK FOLKS!!!!!!

    Leave a comment:


  • jimmbo
    replied
    Does the Stator look the same as the Original, as in same number of coils?

    Leave a comment:


  • comstox
    replied
    I guess I really want to know if CDI Stators have a different "Pulse" setting than my old original Mercury Tach? The CDI paperwork for my new CDI stator said nothing about it. Here's a picture showing my pulse setting adjustment.
    Tachometer Pulse Adjustment

    Leave a comment:


  • comstox
    replied
    Originally posted by jimmbo View Post
    Don't forget about the ground
    Well, we were out with the boat yesterday and while driving the boat I reached under and tried to see if anything was disconnected or loose.... I became the ground! ZAP! It didn't hurt but I was wondering about ground myself. All of my other instruments, (Which share the same ground,) still work, so I doubt it's the ground. AND.... My new rectifier arrived in the mail while we were out on the lake! I'll install it after church today and see if it works!
    Thanks for the feedback!
    Glen

    Leave a comment:


  • jimmbo
    replied
    Rectifier could be bad, or some where between it and the tach, the circuit is broken. Don't forget about the ground

    Leave a comment:


  • comstox
    replied
    Helloooooo... is this thing on?

    Leave a comment:

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