6Y5-8350T-D0-00 Tachometer Install

[fairdeal]

The hour meter runs only when a tach signal is received.

The tach signal comes from the ECM,
through the green wire of the main 10-pin cable,
then to the tach.

You should check the connection and wire integrity
starting with the green wire coming out of the tach
(the individual green wire that ends in a bullet plug)
and follow it
to where it is connected to a green wire coming off the keyswitch.

If that checks out OK,
separate the connector black plug at the keyswitch
and inspect the pins & sockets

then separate the black plug at the engine,
inspect those pins & sockets.

Or you can start by confirming continuity
from the engine plug, to the green wire at the tach
here is the pinout for the engine/harness plug:





You can test for the signal itself,
when the motor is running,
if you have a meter that measures Hz
it is an AC current, whose frequncy is proportional to rpm

[SaltyKayak]

Thanks fairdeal.. I just made another post before reading your reply.. and I will begin checking the integrity... But, I just came in from visually checking the green wire in several places and pulled apart the bullet plugs and reinserted.. they all looked good and clean.. but I was unaware that the green wire connects to the key switch. I will pull the key switch check it in the morning.

[JohnF500]

New member- read through this post as similar issue. 6y5 gauge with a 2013 F150XA 4 stroke- all
original . Everything runs fine but overheat lamp flashes. No alarm, no limp mode. Took to dealer- he set DIP switches to 2 stroke and gave it back- which turned off the Overheat but turned on all oil lights. Thermostat checked, thermoswitch checked, temperature while running within normal per dealer- but couldn’t figure it out and after 2 weeks gave me back boat-They advertise a ‘ master technician’.
I unplugged the 4 wire connector To the gauge- Gray, pink, green with red, and green with white Wires. - turned key to on- and individually used a jumper wire to connect each wire in 4 wire Connector to other half Of connector one at a time. The green with white is connected to a solid green wire- and when connected the overheat lamp flashes. But when I try to trace the green wire it seems to go to the air sensor on the engine- not a temp sensor?
I did read that the overheat lamp flashing could be water in the fuel water separator- but not sure how possible as that is not wired. Had full service 20 hours ago (when I bought it used) and this just started. Engine has 240’total hours.

[JohnF500]

Studying online and now I see there is a thermoswitch by the thermostat and a engine temp sensor on the other side on engine. Will pull and check the resistance of that sensor while I heat it in water... hope a bad sensor is the cause.

[fairdeal]

On a modern engine like yours,
the overhear warning lamp is 'turned on' by the ECM,
'logically' based on input from temperature sensor or switch,
not by direct wiring between lamp and switch.

At the engine,
where the 4-wire "Trim & Oil Harness" from the tach connects,
the pink w/ black stripe wire in the engine plug
is the ECM ground which illuminates the overheat indicator.

You can certainly test the thermoswitch:
it should be open (no continuity between its leads)
at room temp -
and should not close (have continuity)
until its temperature rises to between 183 - 194 degrees F

[NeverSea]

Thanks fairdeal.. I just made another post before reading your reply.. and I will begin checking the integrity... But, I just came in from visually checking the green wire in several places and pulled apart the bullet plugs and reinserted.. they all looked good and clean.. but I was unaware that the green wire connects to the key switch. I will pull the key switch check it in the morning.

Hello friend
Now I have a problem like you.
How did you fix it?

[SaltyKayak]

Hi NeverSea.. I have some 'bullet' connectors coming tomorrow from Amazon to properly connect a green wire from the bullet connector that comes out of my deck inside the console.. to the bullet connector that comes out of the back of my tach. So far, it appears as though I have a break in the green wire (corrosion I assume) between these 2 connectors.

[NeverSea]

Hi NeverSea.. I have some 'bullet' connectors coming tomorrow from Amazon to properly connect a green wire from the bullet connector that comes out of my deck inside the console.. to the bullet connector that comes out of the back of my tach. So far, it appears as though I have a break in the green wire (corrosion I assume) between these 2 connectors.

Mine checked the main cable (10 pins) from the engine and checked the wires from the 703 control to the gauge with all signal multimeters.
I wondered if the output gauge was 0 rpm and showed the same hours by starting the engine.
My gauge has yellow, black, green, blue and sensor trim cables (no wire red).

[NeverSea]

The hour meter runs only when a tach signal is received.

The tach signal comes from the ECM,
through the green wire of the main 10-pin cable,
then to the tach.

You should check the connection and wire integrity
starting with the green wire coming out of the tach
(the individual green wire that ends in a bullet plug)
and follow it
to where it is connected to a green wire coming off the keyswitch.

If that checks out OK,
separate the connector black plug at the keyswitch
and inspect the pins & sockets

then separate the black plug at the engine,
inspect those pins & sockets.

Or you can start by confirming continuity
from the engine plug, to the green wire at the tach
here is the pinout for the engine/harness plug:





You can test for the signal itself,
when the motor is running,
if you have a meter that measures Hz
it is an AC current, whose frequncy is proportional to rpm

The picture shows the cable from my engine. There are 9pin
But I use the main cable to connect the engine to the control 703 10 pin
And the cable goes out of control, black, yellow, green to black, yellow, green, and blue gauge.
But my gauge has black, yellow, blue, green cables and sensor ports
All devices are correct, what is wrong? Please help
My problem is Engine cycle and dead hour

[SaltyKayak]

Been pulling plugs apart, running bypass wires, testing continuity.. and going slow so I don't mess something up something I might have to have the Yamaha dealer fix. But, this is what I have found out so far.. No bad connectors under the console. Also, no green wire to the key switch. Also, no 10 pin plug. I have an 8 pin plug and branching off of it is a 5 pin plug with a green wire. (I am assuming for now, that that is the green signal wire from the engine). Here are some picts of the 'progress so far..

[fairdeal]

[NeverSea]

Have real pictures Of connecting lines from the control to the gauge?

[NeverSea]

Been pulling plugs apart, running bypass wires, testing continuity.. and going slow so I don't mess something up something I might have to have the Yamaha dealer fix. But, this is what I have found out so far.. No bad connectors under the console. Also, no green wire to the key switch. Also, no 10 pin plug. I have an 8 pin plug and branching off of it is a 5 pin plug with a green wire. (I am assuming for now, that that is the green signal wire from the engine). Here are some picts of the 'progress so far..

I will wait for you to update. After accomplishing it

[JohnF500]

On a modern engine like yours,
the overhear warning lamp is 'turned on' by the ECM,
'logically' based on input from temperature sensor or switch,
not by direct wiring between lamp and switch.

At the engine,
where the 4-wire "Trim & Oil Harness" from the tach connects,
the pink w/ black stripe wire in the engine plug
is the ECM ground which illuminates the overheat indicator.

You can certainly test the thermoswitch:
it should be open (no continuity between its leads)
at room temp -
and should not close (have continuity)
until its temperature rises to between 183 - 194 degrees F

Thanks Fairdeal
I see where I made the mistake tracing the wire back and now see where the gauge wires connect to the pink and specifically the pink with black. The thermoswitch closed at 190 degrees F. I pulled the thermosensor and found a temp/resistance chart and it tested within an ohm or two of service guide. I’m going to unscrew and check the fuel filter tomorrow - I don’t see why that would set off overheat lamp- but I’m willing to try anything.

[JohnF500]

Fuel filter was fine, the sensor in that device works properly as well- not the issue. Went through all the grounds at battery and ground block and all good. Going to have the admiral check the gauge while I do the shake and pray on the wires under the console.