omc tach

[wayne 13]

i had a new cd pack put on now the tach is not working all the time. it will work and stop, drop back to "o" but the motor runs <br />great. could a loose wire cause this?

 

[almost retired again]

Re: omc tach

Hello Wayne,<br />Yes it could be a loose wire,but it's kinda hard to give you much help without knowing what kind of rig that you have. Let us know and I'm sure someone will help.

 

[Ross J]

Re: omc tach

Hey wayne 13,<br />you don't say what the motor is other than OMC.<br />The tach only goes when the charging system is working. Thus you need to do a small series of tests to determine where else the fault is. I would think there's a bum connection there somewhere. Go back and re-check all connections you undid & re-did. Especially the ground wire.<br />Check the rectifier diodes & check the stator windings.<br />You don't say if the unit was going OK before the repairs were done?<br />Ross

 

[petryshyn]

Re: omc tach

Hi w13<br /><br />Leave the tach wires connected, take a voltmeter set to a/c volts and measure the tach signal at the back of the tach. (Red lead from voltmeter goes to gray wire on tach. Voltmeter black lead goes to a known good ground) while watching the tach and the voltmeter, see if the voltage goes away when tach dies. This test will verify the tach signal. If this a/c voltage remains at the same level, but the tach quits, you've just ruled out the engine components.<br /><br />If the tach signal stays, and the tach dies, check the accessory lead (+) on the tach. Its the one that is live when key on. If its OK and the tach still dies, check the ground lead on the tach by setting the voltmeter to dc volts and connecting the red lead to tach ground and the black lead to a known good ground. You should get no reading.(if you do, the ground is bad.)<br /><br />This is pretty generic unless you have a motor from the 50's or 60's<br /><br />