Yamaha Tach went dead ?? Whats up ??

S

SEA3PO

New member
My tach on one of my 2003 Yamaha 40's just reads "0" ....this happened after hauling the boat several thousand miles.....
I am thinking the signal for the tach comes from the alternator....right ?
I chacked all the connections....nothing loose...nothing out of place.... motor starts and actually runs better than it usually does....
Did the alternator die ??

Ideas ?

Thanks

Joel
SEA3PO (now in Mobile, Al.)
 
Joel-

I should think the signal on your carburated 2003 40's should come from the distributor, not the alternator.

On later models with electronic fuel injection, it probably comes from the ECM/ Electronic Control Module / "brain" / computer.

Just a thought!

Joe.
 
I don't think there is a distributor...... I think there is a control unit...with a coil for each cylinder..... probably uses a crank trigger for the inpulse....but in that the motor runs better than usual.... I was thinking the tach signal was frequency generated....??? being on the road...nothing to much do but look at it... Hopefully be near Wefings in a few days....maybe I can get it into their shop... this being without a tach really bothers me....

Joel
SEA3PO
 
Joel-

I think you're right about their not being a distributor and each cylinder having it's own coil/trigger unit. Maybe one of these is keyed to the tach with a single wire?

Have you looked at the back of the tach to see if there's a set screw/switch for 2/3/4/6 cylinders and if it's maybe slipped off it's setting and stuck between two different settings?

Do you have a digital VOM meter? Can you tell if an electrical signal is being sent to the tach by testing the incoming wire at the rear of the tach?

Is the tach grounded well? Seems that to work, the signal from the engine would have to run through the gauge to the ground solidly.

The wire carrying the signal from the engine to the tach should, by ABYC standards, have a standard color code of Dark Gray. Would this help you find the tach wire's origin in the engine?

Still trying to help!

Joe. :teeth :thup
 
Joel,

I am not sure what the back of your tach looks like, but there is a switch on the back of the tach for my Honda 90. It is used to select between the number of cylinders on various engines. On my first H90, I had trouble with the tach reading extremely high, and I thought that I had a slipped prop. When that didn't prove to be, I looked at the tach, and moved the switch around to the various positions. It then read correctly.

If there's any moral to the above story, it's probably that you may want to check to see if your tach has a similar switch, and if it is not in the proper position for your engine.

Just a thought.

Steve
 
Nope...no switch...there is a push in button......but if I were to guess...I would think that to be a hour reset..... I did check the grey wire and make sure everything was grounded well...... I just don't seem to be getting anything from the motor as far as a signal....... Guess the best thing to do is wait till I can have Wefings look at it...... I see they service Yamaha motors......plus these things have never run very well.....it might all be connected ....... neither motor will transition well
and usually dies during transition.... runs fine a idle and hight speed...

The really funny thing is, once the tach quit.....that motor seems to run much better..... it may just be me though... imagining things...

Joel
SEA3PO
 
Joel,
Unless you are getting some other important data from the tach, why worry? If it happened to me, I have twin hondas, I would continue my trip, set the throttle to match the other, and relax and enjoy my trip. When you get back home you can troubleshoot it. I would want to confirm that the alternator is ok.
















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Steering is working just great.... one day we went out in some fairly rough water....quartering us... really gave it a workout... and everything went just super...much easier to handle... even the autopilot is working well with it.... Thanks Again for it Roger.... it really is an improvement...

Joel
SEA3PO
 
IT,S A LOOSE BATTERY CONNECTION! If left uncorrected it will burn out the charging coil in your motor. It has happened to me. Tighten those wing nuts with pliers not thumbs.
 
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