85HP Johno Tacho Problem

[imported_JamesL]

Hi Guys,
I have an older modle 85hp Johno and am having problems fitting a new tacho. I have a constant 12V supplied to the red and black wire when the ignition is on. there is a purple wire there from an old broken tacho which i thought would be sending the rpm from the motor but when i plug it in and start the motor nothing happens. with the ignition on i measured 4V between the purple wire and the black wire.
Any suggestions on why it wont work?

 

[ezeke]

Re: 85HP Johno Tacho Problem

The purple wire is positive voltage from the ignition. The sender wire is grey.

 

[imported_JamesL]

Re: 85HP Johno Tacho Problem

The purple wire is positive voltage from the ignition. The sender wire is grey.

where abouts should the grey wire connect on the motor?

 

[ezeke]

Re: 85HP Johno Tacho Problem

If it were a 1982 model, the grey wire would connect at the engine terminal block to the yellow and grey wire from the stator and timer base.

The rectifier would have one of its yellow wires connected to the same terminal or one that is crossed over to it.

 

[imported_JamesL]

Re: 85HP Johno Tacho Problem

Thanks for that!!
Do you know what sort of voltage i should be getting through the grey wire?

 

[F_R]

Re: 85HP Johno Tacho Problem

The gray wire carries AC voltage because it isn't rectified yet. And it isn't 60 Hz AC. I doubt the tach really cares how much voltage it is. It is only counting the pulses.

 

[DJ]

Re: 85HP Johno Tacho Problem

JamesL,

You have two topics going with the same question. Please do not do that. It is confusing and duplicates effort for those that want to help.

Your other post is below.

where abouts can i find a wiring diagram to wire up a tacho?
Any help would be great





F_R


7 / 2006

post # 997 of 1000




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71.101.219.135 Post Subject: Re: 85hp johnson Posted: 4:14pm Today
I have some of them, but need a year or model or something in order to know which one to give you.






WillyBWright

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12 / 2003

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75.51.10.31 Post Subject: Re: 85hp johnson Posted: 4:17pm Today
If it's reasonably new,
Black to Neg or Gnd
Purple to Ign
Gray to Sig
Blue to light


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JamesL


2 / 2007

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202.7.176.131 Post Subject: Re: 85hp johnson Posted: 4:21pm Today
Its an older V4 think its about 1980's. what kind of voltages should i be getting from the sender?