Tacho signal

[nfrnkish]

Where in the engine does the tacho get it's signal from? What should be the range of voltages on this wire - can't find a single mention of any tacho signal in my Seloc manual. Mercury 115 HP 4 cyl. 2 stroke.

 

[achris]

Re: Tacho signal

Usually from one of the leads from the battery charging coils in the stator. On the later model engines with regulators, there is usually a seperate terminal on the regulator for the tacho.<br /><br />Let me know the serial number of your engine and I should be able to identify it for you. I may even be able to post a picture It's easy to see why you're having a problem finding it. Seloc!<br /><br />Chris..........

 

[nfrnkish]

Re: Tacho signal

Engine Ser. No. is OG198241

 

[achris]

Re: Tacho signal

The grey wire from the voltage regulator is the tacho signal. It goes straight into the harness plug in the engine and should be present at the intrument harness connector on the control box. If you have the standard control box that comes with the engine you'll find a 5 pin connector on a lead coming from the back of the control box. A harness plugs into that which has all the necessary wires in it. The signal wire for the tacho should also be grey.<br /><br />Hope that helps.<br /><br />Chris...........<br /><br />EDIT : If you don't have wiring diagrams, post your e-mail address and I'll send to you.

 

[nfrnkish]

Re: Tacho signal

Thank you very much! I have the Seloc manual and can see a grey wire from the regulator via a terminal block to the harness connector. I will have to wait to see it in reality! Any idea what sort of voltage I might expect? I can trace the wire to see if I have a break, I supose. <br /><br />I sort of expected a connection with the rev limiter, which I'm also having a problem with: the rev limiter is grounding the second kill wire. I thought that my tacho problem was related, but it seems not...<br /><br />Thanks again,<br /><br />Neil.

 

[achris]

Re: Tacho signal

neil,<br /><br />The rev limiter has nothing to do with the tacho. They are competely seperate in this case. The 'voltage' on the tacho wire will be 0 with the engine not running. With the engine running it's the frequency that drives the tacho, not the voltage. I have no idea what the AC voltage would be, I suspect around 14 volts, but it will be AC not DC.<br /><br />If you're looking to see if the wire's broken, then disconnect it at the regulator end, short it to ground at the control box end and then just check for continuity to ground back at the engine end. Just be sure to disconnect the battery as a safety precaution.<br /><br />Chris.........