Hour Meter

[RumLine II]

I know this is not a new request for information on hour meters but I've read through all the forums I could find and haven't found an answer that will aid me in my installation. I have a Yanmar 4JH4 xxx engine and I need to install an hour meter on it. I have the meter and I need to know where I can hook the power wire to. I have no access to the ignition key only the engine. I have read you can hook it up to the alternator but they don't say which wire to attach it to, as well some say don't use the alternator as it puts out too many amps. I ve seen hor meters on engines before but never took the time to see where the wires were attached to. I believe it can be done but I need help......
Gary

 

[Ralph Johnstone]

. I have no access to the ignition key only the engine.

Unusual that you can't get into your ignition key as there are numerous points you could take off for the hour meter.

As you can get into the engine, use one of your alarm circuits such as low the oil press. switch or high water temp. switch. I recently needed put in a relay down in the engine compartment and used a Croydon DC60S solid state relay on the oil press. switch wiring. You don't want to draw anything over a few milliamps on the alarm circuit or you'll activate the audible alarm. The one I used draws 2.2 ma which is not enough to activate the alarm.

Unfortunately, now you're going to have to run the relayed wiring back up to the steering console where I imagine the hour meter is going to be located and probably no more than a few inches away from the ignition key. Again, it would be so much easier to get a keyed electrical supply from the ignition key if possible.

 

[Bill Roosa]

Agree with Ralph. You are going to be taking the engine instrument panel off which probably has the ignition switch on it so why not use that?
good luck.

 

[RumLine II]

Thanks for your response guys, and your right about the easy hook up to the ignition. But my hour meter is mounted on the engine compartment wall, to go to the control would require about 15 ft. of feeding wire up to the panel through floor, walls and outside panels.
I'm not too excited to tap into an alarm circuit. I see a few wire terminals on the engine that I expect are for options accesories, I'm wondering if one of these could be used......? I think there is a plug for a second panel somewhere but I don't have a schematic.
Who would think it would be so difficult to find 12 volts on a engine.!!

 

[Ralph Johnstone]

Now That's a Whole ..............

But my hour meter is mounted on the engine compartment wall,

........ different matter.

The wire spare terminals on the engine (as you've mentioned) may offer some help in finding the electrical supply you require.

If I can suggest, with the engine off, use a voltmeter between each wire and ground and make a list of who's live and who's not.

Then, making sure that all of these wires are very easily accessible, start your engine and once again check each wire for power. I won't bore you with the need for safety here .

If you find a wire that is energized ONLY when the engine runs, you're off to the races. Use #16 wire as your hour meter will have near zero amperage draw.

But as you well know, life's a bi*ch and then you die so don't hold out too much hope for this.

Moving right along, you're next step (assuming this didn't work) is to go into an alarm circuit and install your meter. In my previous post, I went a little overboard and suggested using a solid state relay. Taking a second look at this, you MAY (as in might, possibly, or be really lucky) be able to insert the meter in parallel with the alarm circuitry without activating the audible alarm. I needed a relay as I was looking for 3A.

Looking at the attached diagram (better still, see post #6 below), I am hoping that your hour meter has such a high resistance that the new wiring for the meter DOES NOT offer an alternate route for the electricity to flow to ground and activate the audible alarm. I'd suggest a pocket full of cheap alligator clip wires and try this out to make sure the meter does not conduct enough electricity to sound the alarm.

Send me a PM if you need any further guesstimation on this.

 

[Ralph Johnstone]

Minor Correction ..............

................ on that alarm circuit drawing above . Sorry about that, RumLine.

Trying to watch the Superbowl game and draw pictures at the same time .............. the results are predictable.

 

[RumLine II]

Re: Minor Correction ..............

OK his sounds do-able. I'm not sure if the fact that I have oil pressure and water temp gauges in my C-Type Panel. It also has the warning lights and buzzers. I'm hopping that the sending units are usable. I'm going to try and check things out on the engine today. Thanks for the help and I'll let you know how I make out......
Gary

 

[Benny17441]

I would rethink the need for installing the hour meter in the engine compartment. Such instrument is most useful in the cockpit. We use our primarily to monitor fuel consumption. It is convenient to be able to calculate how much fuel left when underway by just glancing at the hour meter. We also use it to schedule maintenance and is also easier to monitor without having to open the engine compartment. Mounting it next to the control panel allows the meter to be installed across the key switch terminals so that turning the key activates the counter. Many are hesitant to drill holes but done properly yields good results. Check out the size of the hole needed and drill through masking tape to avoid cracks in the gelcoat. Use a sealer to weatherproof the opening and connect the wires and re-install the panel.