Aqua meter tach on a V-4 Johnson

[larryejoh]

I have an old Aqua Meter tach with a black and grey wire. I am using it on a 59 Johnson 50 hp.There is a set screw that will change the pulses from 1-6. I believe I hook the black to ground and the grey to the wire coming from the mag to the ignition switch. What pulse do I set the switch to?

 

[wilde1j]

Re: Aqua meter tach on a V-4 Johnson

If you have a 12 pole stator, the switch is set to 6P. If you set is wrong, there will be no harm done ... it just won't read right. Set it at 6 and see what it reads at idle (should be ~ 650 to 750 in gear in the water).

 

[F_R]

Re: Aqua meter tach on a V-4 Johnson

That motor doesn't have a "stator", or "poles".

The next question is just what is the tach designed to work on? My best suggestion is to set it to 4, hoping it is designed to get its pulses from the ignition system, which is what you need. There are 4 pulses per revolution available at the stud on the side of the magneto (or one of the black wires at the igniton switch--the other black wire is ground)

If the tach is designed to work on an altrenator stator, you are out of luck.

Many Aqua Meter tachs require a transmitter. Hope yours isn't one of that kind, unless you have the transmitter.

EDIT: Those 4 pulses at the magneto are two (+) pulses and two (-) pulses. Kind of underscores the need to have a compatible tach.

 

[Aurel921]

Re: Aqua meter tach on a V-4 Johnson

Hi Guys,

Actually, I am looking for a transmitter...

Let me know if you have one of these transmitter for sale.

Otherwise, do you have an idea to fix my problem (rebuilt a new one,...)?

Thank you

Aurelien