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Can 2021 Yamaha t9.9 support a remote hour meter?

C

Catalamarc

New member
I am geting new t9.9s for my cat which has an hour meter which I beleive gets it's power from teh wire coming off the oil pressure switch on teh older models. THe newer ones do not have a second connector on the wire but I was wondering if teh old wire could be sued and run teh meter that way?
 
Boscoe, I read your 2017 bost about installing a diode to power a meter/light. I was thinking of a more automotive solution and figuring out how to use a relay. The inductive meters/tachs are not practical as the motors are in wells and the boat, a 36 ft. cat, operates from a console. Don't know enough about tachs but could the tach signal from the engine drive the hour meter? I am even trying to get someone at Yamaha to explain to me why I can't simply replace the wire between the oil pressure switch and the CDI with the older style Yamaha wire and run it off that or to give me a waranty proof permission to do that.
 
Yams don't normally use a relay in connection with the tachometer. The motor outputs a tachometer signal. Tachometer is normally positioned at the helm and gets battery positive and negative there. A wire from the motor to the tachometer conveys the tachometer signal.
 
Yamaha oil pressure switches don't normally provide power. They may get a bit of power from the CDI unit but that is really just a reference signal. When the pressure switch closes due to a lack of oil pressure the switch closes and completes the circuit to ground. The CDI interprets the ground as being a loss of oil pressure.
 
Older yamahas circa 2000 ran a yw/red wire from the wire connecting the oil pressure switch to the CDI. That went to the Blue wire in the remote harness. While what appears to be a similar switch and CDI are present in the current motors, the yw/red wire is not present. In the old Yamaha ignition panel like mine that blue wire ran an oil presssure light and I believe powered the hour meter. The newer motors have an identified tach signal coming from the motor to the harness but I do not think thet older ones did. I just don't know enough about how tachs work to know if it could also power the hour meters.

I am still waiting for the new motors but they are 2021/22 XWHB's converted to remote control and to the 7 pin harness. Teh boat was designed around a pair of manual tilt outboards in wells.
 
The Y/R wire was used to turn a low oil pressure light on/off. Have no idea if, and, or how it was used to provide power to a tachometer.

Yamaha data shows key on battery power (from the motor via a red wire) being provided to a tachometer via a yellow wire. Black wire from the motor provides a ground to a tachometer. Green wire is the tachometer pulse signal. See below.

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Thanks, that Tachometer drawing helps. The old setup did not have a tach but the yw/red wire appears to have supplied power to the hour meter (which I just replaced and now might not be able to use). That seems to mean that in the older motors, the pink wire btween teh oil pressure switch and the CDI was HOT while the engine was running. But if the switch breaks the circuit if oil pressure is low then the light ought to remian on unless something else cut off the power to the wire. Confusing.
 
In hindsight I should have used the words "hour meter" in lieu of tachometer. The same power source and ground are used for both instruments.

I am completely lost and baffled as to how or why anyone would use power to an oil pressure switch to power an hour meter.
 
I use a little hour meter that has a wire you wrap around the spark plug wire. Mount meter on motor under the cover. Cheap, less than 15.00. Works great for maintenance intervals.
 
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