No RPM on Digital Tach!

[CatCam]

I just trailered my boat back to my house from the camp because I needed to pull my carbs to clean out the low speed jets..... Anyway, put everything back together and the motor runs fine again...BUT I'm not getting a tach reading on my Yamaha Multi-Function Outboard Tachometer. Everything else on the Multi-Function Tach works (hour meter, tilt angle indicator, oil, etc)..the tach just reads '"0"........

Motor is a 2004 Yamaha 90 Four Stroke...

I did not run the boat when I came home, I just proceeded to pull the carbs. I checked all the wire connectors on the motor and under the steering console, everything is good, I disconnected and connected all the connectors, everything is tight.

Should I open the Remote Control Box (Yamaha 703) and if I do what color wires control the tach????

Thanks!!
CatCam

[boats.net]

Check the green wires at engine to see if one is disconnected.

[CatCam]

All connections "seem" good. If I put a multimeter on the green and black wires what should I be reading at idle?

Thanks!!

[boats.net]

Set meter for AC voltage and you should see voltage increase as rpm's increase.

[CatCam]

Not good -- No voltage measured......

I checked my meter, plugged into AC socket, measure 115VAC...nothing on green wire & black while boat was running.

I did a continuity check on the green wire from the motor plug in harness to the green wire connection point that comes out of my 703 remote box and it Ohm checks good.

Any pointers for "Plan B"?????

Thanks a bunch,
CatCam

[boats.net]

You would need to test alternator on engine, CDI, 10 pin main harness and all wiring connections.

[CatCam]

I'll check out the electrical connections tomorrow. Let's keep our fingers crossed that this is the culprit as I really don't want to shell out big $$$$ for a CDI! I'll post my findings!

Thanks to everyone so far for their help.

CatCam

[CatCam]

Well, I unplugged and replugged all my connections from the CDI and my 10 pin main harness....ohm checked everything I could and all looks good. My alternator seems to be working well, My Yamaha LCD Speedo battery goes up to like 14.6V when I rev the motor up.

I guess I have it narrowed down to the CDI.....that SUX because it isa $300+ part......unless anyone has one laying around in their spare parts bin!! hehehe

CatCam

[CatCam]

I'm all ears for a work around!!

[CatCam]

Oh...I see. Looking at the wiring diagram the red wire runs from the regulator into the CDI. If I disconnect the green wire that comes out of my CDI and then tap the red wire and connect to the green wire heading to the tach I should be back in business.
Just-in-time - am I on the right train to freedom here??

Thanks!
CatCam

[CatCam]

Got it!
Green to Green!
I'll give it a go tomorrow!!

Thanks a bunch Just-in-time!!

CatCam

[CatCam]

Okay - There are two plain dark green wires and one green/white coming from my voltage regulator. I tapped into one of the plain green wires and ran this straight to my green wire that feeds my tach. Cranked her up and got 8 x100 on the meter! I thought all was good to go until I revved up the motor a bit and the tach actually went down to 6, 5, 4, 3 when I went back to idle it went back to 8 x100! weird.

Anyway, I removed the wire and I'm back to square 1.

I wonder if the voltage regulator is the culprit???

[CatCam]

There are 5 wires coming from the voltage regulator, 2 green, 1 green/white, 1 black, one red. I hooked into one of the green wires.....RPM's read 'backwards". At idle 8 x100, as I idled up the LED RPM reading went DOWN. Am I on the correct wire?

[CatCam]

There are 5 wires coming from the voltage regulator, 2 green, 1 green/white, 1 black, one red. I hooked into one of the green wires.....RPM's read 'backwards". At idle 8 x100, as I idled up the LED RPM reading went DOWN. Am I on the correct wire?

[CatCam]

GREAT NEWS!!

Tachometer is working -- I hooked directly up to the "other" green wire from the voltage regulator and I'm in business!

Digital Tach works perfect....So the culprit was the CDI because I have now bypassed it completely for the tach operation......

Thanks "Just in time" for pushing me in the right direction -- You tha Man!!