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75 hp Merc no tach and battery not charging

foulgoose

New member
I have dva tested the stator on both the red and blue wires. Its an aftermarket CDI stator and I got a little over 25v on red when cranking and somewhere in the low 200's on the blue. I DVA tested the yellow to yellow which idk if that a valid test but I was getting like 20 something volts at idle and I felt like it rose proportionately when I revved the engine slightly. I have tested my reg/rec (which is sierra aftermarket) in the way of verifying that both red wires do indeed have battery voltage going to them and my grey wire dva tested at like 11 volts and I know it just needs to be over 8 so it seems like I'm good there as well. I have also pulled the flywheel and made sure I had no burnt windings and have ohmed the stator multiple times and all the numbers read as they should. Long story short I am under the impression that my stator and reg/rec are good. I literally went as far as wiring the tach straight to the engine meaning I took it out and made jumpers and connected grey directly to the send post, connected power straight to the positive on the solenoid, and a ground to a known good ground and still nothing. I have tried this with the tach I already had and also with a brand new tach and all I end up getting is the needle drop when it gets power but never anything else. I have tried rotating the pole selector on the back to every single position through out all of these tests and still nothing. I am almost at a total loss I cant thing of what else I am missing. Also the battery is brand new and I have tried multiple batteries that have been load tested and are 100% known good. I think I have done everything short of connecting the yellow stator bullets directly to the reg/rec itself. Oh and I even bought a replacement cdi reg/rec and hooked it up and it was still the same story. The motor is somewhere between 1994 and 1997 3 cyl 2 stroke.
 
On my OB, the tach was fed off the Voltage Regulator.
It was 100% blown out. so no tach/ no charge.
Newer ones do not always have a tach output from the Voltage Regulator.
So if it was replaced.. it could have been installed with one that has no tach out.
Consider getting an inductive tach that wraps a wire around a spark plug wire to sense the rate of fire.
 
Connecting the tach directly to ungrounded AC may not work if the rect is bad...depending on what's bad. The tach needs a ground reference and the AC leads from the Stator are floating. With what you tested, your results, and the problem you are having I'd opt for a new rect-regl module. The tach counts rectified, ground referenced half cycles.
 
Connecting the tach directly to ungrounded AC may not work if the rect is bad...depending on what's bad. The tach needs a ground reference and the AC leads from the Stator are floating. With what you tested, your results, and the problem you are having I'd opt for a new rect-regl module. The tach counts rectified, ground referenced half cycles.

When im DVA testing the grey signal im pretty much getting 11.8 to 11.9 something and its just kinda hanging out there and doesnt seem to respond accordingly meaning output on grey signal wont follow rpms up or down. I would imagine that the reading should rise and fall. Do you know if this is supposed to be the case? I have tried a new CDI rec/reg and i got the same results. I suppose i could try another. Also i just realized the battery is charging i didnt realize that it doesnt put out a substantial charge at idle like a car, which is when i was checking but today i had someone rev it and the voltage went to above 13 so all good there i guess. Im new to fixing outboards.
 
Manual specifies charge rate starting at 1k RPMS and it gets progressively higher as the RPMs increase up to the max at around 4k....kinda levels off as I recall due to the regulator kicking in. Since the tach signal is a rectified stator output to the charging circuit and it does as mentioned, then the amplitude of the tach signal varies also. You did specify a minumum 8 volts and that is about right at idle....without me looking that part up.
 
I switched motors on my 2006 Tracker from a 2006 60 hp Merc to a 1996 75 hp. The tach works fine but,the charging gauge shows minus when I run the boat and I have to charge the battery after ever 2 times I run the boat? any suggestions?
 
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