How to wire up an hour meter?

trobinson017

Petty Officer 2nd Class
Joined
Sep 12, 2004
Messages
183
I have an hour meter I want to install on my boat. It has no instructions at all. How to I wire it up to work only when the engine is running? Nobody I know with a boat even has one so no help there. I'm sure it's simple, I'm just not sure how best to do it.

Thanks!
 

Reel Kahuna

Petty Officer 1st Class
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Apr 3, 2010
Messages
271
Re: How to wire up an hour meter?

Splice in to the volt meter positive side to the positive on the hour meter. Negative side of the hour meter to the ground bar.
 

trobinson017

Petty Officer 2nd Class
Joined
Sep 12, 2004
Messages
183
Re: How to wire up an hour meter?

Splice in to the volt meter positive side to the positive on the hour meter. Negative side of the hour meter to the ground bar.

Hmmm....if I did that wouldn't the hour meter run when I turned on the batteries without starting the engine? I didn't mention that I have 2 batteries with a switch for them so I can use 1, 2 or both. I typically have the engine off and batteries on for the stereo when hanging out at islands. If I did what you recommend, would the hour meter keep running with engine off, batteries on?

Thanks for the reply, btw!
 

phwrd

Petty Officer 1st Class
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Jul 30, 2007
Messages
294
Re: How to wire up an hour meter?

I am trying to wire one to the RPM gauge, only on when the motor is on ? Is this correct ?
 

trobinson017

Petty Officer 2nd Class
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Sep 12, 2004
Messages
183
Re: How to wire up an hour meter?

I am trying to wire one to the RPM gauge, only on when the motor is on ? Is this correct ?

That sounds like a good idea. I hadn't thought of that. But, I dont' know if that would work. Hopefully, Reel Kahuna or another experienced boater can provide the answer.
 

dwco5051

Commander
Joined
Sep 14, 2008
Messages
2,326
Re: How to wire up an hour meter?

No, do not hook up to the tach. It would help to know what motor or engine (outboard or inboard) you are hooking up. There should be an accessory terminal on your ignition switch that supplies 12v to radios and such. If this is an OMC outboard it could be the violet wire. A check of your ignition switch terminals with a multimeter or test light will show which terminal is hot when the key is on.
 

dwco5051

Commander
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Sep 14, 2008
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2,326
Re: How to wire up an hour meter?

I should of read the signature on your post before I wrote my reply. I take it this is for the 99 130 johnson. Check the back of the switch and look for a violet wire. It wouln't hurt to check with a meter to be sure that is the one that is hot when the switch is on. That is the wire you would connect the positive on the Hobbs meter to.
 

brianvolt7

Chief Petty Officer
Joined
Jun 7, 2008
Messages
423
Re: How to wire up an hour meter?

The key is to find an electrical source that is only positive or negative while the engine is actually running, otherwise whenever your key is in the on position it will be recording hours.

You will need a multimeter to determine this, and you have your work cut out for you if you don?t have a dedicated output made to run an hour meter.
 

Reel Kahuna

Petty Officer 1st Class
Joined
Apr 3, 2010
Messages
271
Re: How to wire up an hour meter?

Hmmm....if I did that wouldn't the hour meter run when I turned on the batteries without starting the engine? I didn't mention that I have 2 batteries with a switch for them so I can use 1, 2 or both. I typically have the engine off and batteries on for the stereo when hanging out at islands. If I did what you recommend, would the hour meter keep running with engine off, batteries on?

Thanks for the reply, btw!

Your volt meter is connected by the purple wire that's mentioned above. It's only activated with your ignition switch is turned "on" and is "off" when the switch is turned off.

Your stereo is connected (or should be) by a different wire that's a constant "on" voltage, like your bildge pump, blower, anchor light(s) and vhf radio.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: How to wire up an hour meter?

You are out of luck. An hour meter is a clock that requires switdched 12 volts and ground so it will run as long as the key is on -- engine running or not. But the question is -- why do you leave the key on. You cannot hook it to the coil because that is a pulsed signal. You cannot hook it to the tach as the "S" terminal is also pulsed and besides, it is nowhere near 12 volts. You simply have no option unless you design a circuit that actually can be triggered by the tach signal.
 

trobinson017

Petty Officer 2nd Class
Joined
Sep 12, 2004
Messages
183
Re: How to wire up an hour meter?

Great replies by everyone!! I think I'm starting to understand how to hook the meter up. My key is never on unless the engine is running so the volt meter idea by Reel Kahuna sounds like an easy thing to do. If it doesn't appear to work I'll try to find a proper contact on the ignition switch.

Thanks everyone!!
 
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