Can anyone give me an idea of how hard it is to wire in an hour meter on a 1988 Yanmar 2GM20 diesel? My O'Day 302 doesn't have an hour meter and I'd like to add one if it's not too difficult. Are there any brands/types someone might recommend? Thanks to all in advance for your thoughts and experience.
Wiring in an hour meter?
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Hobbs Meter
There are two basic methods for wiring an electric engine Mour Meter. The most common is to wire the Positive side of the meter to the "run" or "on" terminal of the ignition switch. The disadvantage to this installation is that the meter will run anytime the switch is in the "on" position, even if the engine is not running. The preferred method is to wire the Positive side of the hour meter through a normally-open engine oil pressure switch. When the engine starts and the oil pressure reaches the set point of the switch, the contacts will close turning on the hour meter. This method gives a true indication of engine run time. In both cases, the "other" wire is Negative.
There are two basic methods for wiring an electric engine Mour Meter. The most common is to wire the Positive side of the meter to the "run" or "on" terminal of the ignition switch. The disadvantage to this installation is that the meter will run anytime the switch is in the "on" position, even if the engine is not running. The preferred method is to wire the Positive side of the hour meter through a normally-open engine oil pressure switch. When the engine starts and the oil pressure reaches the set point of the switch, the contacts will close turning on the hour meter. This method gives a true indication of engine run time. In both cases, the "other" wire is Negative.
Hay Gord
I thought the low oil pressure switch was open during engine operation. At least on my boat the ignition switch supplies power to the oil pressure switch which is closed when the engine is off (no oil pressure) allowing the light and buzzer to sound. Then the engine starts, the oil pressure comes up and the switch opens stopping the light and buzzer. After rereading your post I see that you might be suggesting that in addition to the normal oil pressure switch to control the light and buzzer you install an additional oil pressure switch to control the hobbs meter. Did I read you correctly?
I thought the low oil pressure switch was open during engine operation. At least on my boat the ignition switch supplies power to the oil pressure switch which is closed when the engine is off (no oil pressure) allowing the light and buzzer to sound. Then the engine starts, the oil pressure comes up and the switch opens stopping the light and buzzer. After rereading your post I see that you might be suggesting that in addition to the normal oil pressure switch to control the light and buzzer you install an additional oil pressure switch to control the hobbs meter. Did I read you correctly?
clarification
Yes, Bill correctly read more than I wrote. Your Oil Pressure Warning Sender is indeed a “Normally Closed” (*1) pressure switch. The Hobbs meter requires that you install a "T" fitting and an additional Normally Open” oil pressure safety switch (extra to the original oil pressure sending unit). (*1) The oil pressure switch is normally closed when there is no oil pressure. This provides a path to battery negative allowing the oil indicator bulb to light constantly (indicating low oil pressure). After the engine is started and oil pressure rises, this switch opens the path to battery negative allowing the light to extinguish.
Yes, Bill correctly read more than I wrote. Your Oil Pressure Warning Sender is indeed a “Normally Closed” (*1) pressure switch. The Hobbs meter requires that you install a "T" fitting and an additional Normally Open” oil pressure safety switch (extra to the original oil pressure sending unit). (*1) The oil pressure switch is normally closed when there is no oil pressure. This provides a path to battery negative allowing the oil indicator bulb to light constantly (indicating low oil pressure). After the engine is started and oil pressure rises, this switch opens the path to battery negative allowing the light to extinguish.
Hour meter
Every connection you make on a boat is a potential problem spot. Remember the KISS rule. ( keep it simple stupid ) Just hook it up to the positive side of the ignition switch. This is what the guages work off of. You might gain an hour or two in a couple of years. Who cares. Hell, you might have to change your oil an hour before scheduled.
Every connection you make on a boat is a potential problem spot. Remember the KISS rule. ( keep it simple stupid ) Just hook it up to the positive side of the ignition switch. This is what the guages work off of. You might gain an hour or two in a couple of years. Who cares. Hell, you might have to change your oil an hour before scheduled.
You may already have a circuit in place.
Steve: I just did this on my 3JH2E. There was a circuit in the wiring harness for the meter. This was something that was designed into the system by YANMAR. Turning off the key without shutting down the engine is a no-no in case Mr. Stephens has never been instructed, so this is not an issue.
Steve: I just did this on my 3JH2E. There was a circuit in the wiring harness for the meter. This was something that was designed into the system by YANMAR. Turning off the key without shutting down the engine is a no-no in case Mr. Stephens has never been instructed, so this is not an issue.
Ignition key off and still running
Not to be redirecting the post, but can someone explain WHY running with the ignition key off on a diesel engine is a "no no"? The reason I ask is I have a crew member that does this all the time (yes, I want to beat him) and I'd like to have a reason to tell him. Clearly the engine itself does not care a wit if there is any electricity to it. I've heard that the "diode pack" will get fried due to high voltages when you do it but my alternator works just fine after numerous "no no" events. My little pin head thinks that when you turn off the ignition you just de-energize the field winding on the alternator and the whole electrical system starts running off the battery. This would preclude the possibility of frying the diode pack as there would only be the residual magnetism in the rotor field to make electricity with. What am I suppose to be breaking by doing this?
Not to be redirecting the post, but can someone explain WHY running with the ignition key off on a diesel engine is a "no no"? The reason I ask is I have a crew member that does this all the time (yes, I want to beat him) and I'd like to have a reason to tell him. Clearly the engine itself does not care a wit if there is any electricity to it. I've heard that the "diode pack" will get fried due to high voltages when you do it but my alternator works just fine after numerous "no no" events. My little pin head thinks that when you turn off the ignition you just de-energize the field winding on the alternator and the whole electrical system starts running off the battery. This would preclude the possibility of frying the diode pack as there would only be the residual magnetism in the rotor field to make electricity with. What am I suppose to be breaking by doing this?
You lose your alarms if your key is off
If you turn your key off you lose power to your guages and you lose your high temp alarm and low oil pressure alarm and any other indicators that are connected to your key switch. Tell your crew member that he is liable for subsequent damage caused - that should discourage him
If you turn your key off you lose power to your guages and you lose your high temp alarm and low oil pressure alarm and any other indicators that are connected to your key switch. Tell your crew member that he is liable for subsequent damage caused - that should discourage him
And it shuts off the alternator.
There are almost NO reasons to shut off the key. If the alternator is putting out full power then turning it off gives you more power to the prop during an emergency. That and turning off the key at shut-down stops the annoying buzzer. Other than that, you're right. Your crewman is a PINHEAD!
There are almost NO reasons to shut off the key. If the alternator is putting out full power then turning it off gives you more power to the prop during an emergency. That and turning off the key at shut-down stops the annoying buzzer. Other than that, you're right. Your crewman is a PINHEAD!
It's what you don't know that get you
Thanks. That is what I thought too. Guess I have to do the "Dr. Strangelove" thing and Stop worring and learn to love the key being off.
Thanks. That is what I thought too. Guess I have to do the "Dr. Strangelove" thing and Stop worring and learn to love the key being off.
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