F20 Analogue tach?

[merc200dalarna]

I'm just curious if I can attach a generic tach to my 2013 F20. One of those "fits 2, 4, 8 cylinder engines fourstroke"?
I have a digital one now but it won't show rpm above 5000, it jumps all over the place at those rpms.

Is there any of the wires in the harness that I could get the rpm signal from? (or which I can translate to rpm?)

[boscoe99]

Too bad you don't say what model motor you have. Saying it is an F20 is like telling the automobile parts man that you have a Ford and want to buy an alternator. Not all Fords use the same part.

Assuming you have a remote con*****ed model, the green wire in the engine harness conveys the tachometer signal. If a tiller handle model the green wire will be found within the engine cowling.

What you are seeking to do has been done by many. Quite doable.

[merc200dalarna]

Too bad you don't say what model motor you have. Saying it is an F20 is like telling the automobile parts man that you have a Ford and want to buy an alternator. Not all Fords use the same part.

Assuming you have a remote con*****ed model, the green wire in the engine harness conveys the tachometer signal. If a tiller handle model the green wire will be found within the engine cowling.

What you are seeking to do has been done by many. Quite doable.

Yea, sorry. Might be confusion, but I have a european (I'm swedish...) F20 BMH(!!!) I think I remember you have a slight different model system. Anyway, mine is 20' inch, tiller, rope start, manu. year 2013!

[boscoe99]

The H tells me it has a tiller handle. You should be able to find a green wire with a bullet connector at the end of it, under the cowling. That is the tachometer signal.

Not sure how your present tachometer is connected. If not a wrapped around wire type it could very well be connected to the green wire.

[merc200dalarna]

The H tells me it has a tiller handle. You should be able to find a green wire with a bullet connector at the end of it, under the cowling. That is the tachometer signal.

Not sure how your present tachometer is connected. If not a wrapped around wire type it could very well be connected to the green wire.

OK. Nice. I have an old thread where you replied "Boscoe": Yamaha F20BMH 2013 electrical.... where I asked about fitting a starter and a battery charging lead, seems like we are discussing the same green wire that you mentioned then!!! I have a photo of my motor and the coupling box in that old thread. 2 green wires with bullet connectors, both are plugged on the other side. My present tach is a chinese "tiny-tach" wired around the ignition coil. Unreliable but helped me dial idle rpm and counts my hours between oilchange! Thanks.

Edit: Does any of yamaha original tachs fit with almost the same ease? Prefer analogue!

[boscoe99]

Do you have a battery in the boat? The tachometer has to get power and ground from somewhere. Normally a battery.

[merc200dalarna]

Do you have a battery in the boat? The tachometer has to get power and ground from somewhere. Normally a battery.

Yes, got a battery for my Lowrance. And wires running under the gunnel, I'd get the positive from there. So that electric schematic, I'm not trained to read it, but if I suppose the far right is the "coupling box" that comes from the cdi. I'd go negative to ground somewhere on the motor? And then green to the unused green of the motor? I have a black on the motor, can't see any yellow or blue....

[rodbolt17]

G = green.
look at the first diagram.
you will note 3 GREEN wires.
two are coming from the lighting coil and are capped off on your model.
the GREEN from the CDI is a tach signal and is based on pulser coil inputs.