Tach not working

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droutte

Seaman Apprentice
Joined
Jan 8, 2004
Messages
37
I have a 1989 Johnson 150GT. I just installed a new Tach and it will not work. The old one did not work either. I have three wires.<br />Black, grey & Purple. I have black on negative,<br />purple on positive and grey on pulse. The switch<br />setting is hard to tell where it is. It clicks<br />in different settings continuously in both directions. Should I get a reading on all settings<br />if it works? I know the tach would not read right. I have it pointing (I think) at 6.<br /> Where does the pulse wire come from, if I need to run a new wire ?<br /> The rectifier is working, While running the battery reads 13V.
 
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vano6990

Petty Officer 3rd Class
Joined
Aug 3, 2005
Messages
82
Re: Tach not working

If so the arrow on the settings should point the opposite direction of the marked 3P 6C position (about 2 o'clock). The tach also should zero when the power is turned on. If it dosent then the positive IGN or ground are not connected properly. You could check with a volt/ohmmeter and teh IGN+ to ground- must be 12-16 volts DC with the ignition on. Then if the tach goes to zero and wont track RPM it then would be a possible indication the rectifier isnt working properly.
 
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ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Tach not working

I think that if you are getting charging power to the battery, then your rectifier is probably OK. <br /><br />You will want to check the grey wire which runs from the engine to the control and then to the tach to make sure that it is working and connected properly. <br /><br />BTW-Some grey tach wires had diodes imbedded in them.
 
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droutte

Seaman Apprentice
Joined
Jan 8, 2004
Messages
37
Re: Tach not working

I have +12V on the terminals of the tach with the key on. No manf. name on the unit.
 
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droutte

Seaman Apprentice
Joined
Jan 8, 2004
Messages
37
Re: Tach not working

Does the grey wire go into the trottle control<br />box then to the tach?<br /><br />Where does it go on the engine ?<br /><br />Thanks
 
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ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Tach not working

Go here and see part 50 on the control diagram. See your dealer for the harness between it (the accessory plug) and the Tach. Control diagram. <br /><br />The grey wire goes through the main harness to the wiring block at the regulator on the engine.
 
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droutte

Seaman Apprentice
Joined
Jan 8, 2004
Messages
37
Re: Tach not working

I ran a wire directly from the tach to the regulator, and the tach is now working.<br /><br />Thanks
 
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