Cannot find a operating manual to fix a problem

tiltrider1 said:

You did flip the shore/off/generator switch to generator correct?

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yes sir I did that.

So much for the easy stuff. Now you need a multimeter, first test for voltage at the generator. Then test at the shore/gen switch. Test both gen in and power out at the switch. Unplug shore before doing the test.

One thing to note shore/gen switches can fail. It is possible that shore side can work while Gen side won’t. By testing at the Gen and at the switch we rule out two potential big issues very quickly.

dvarholy said:

I have hard copies of the 8MDKD shop and parts manuals. I would suggest, with the power off, trace the feeder cable back from your transfer switch to the generator control box. Let me know if you need more help.

Daniel Varholy
'89 Tradewinds '43 MY

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Hi Daniel, That is awesome! You are saying follow the wires starting at the transfer switch (shore/generator power switch ) on the back side of panel in the main cabin to control box? Is that correct? Perhaps the breaker might be along this route since CB is optional and we now know it is not at control box on the Onan Generator.

You should begin at the generator and confirm AC power output before tracing wires to the transfer switch.
You need to know the GEN is working before tracing where the wires go. IMHO

How would a layman know which of the wires connected to the transfer switch actually go to the Genset? You have a 50% chance of getting it right, if there is also just a shore power connection.
Start at the Genset (thats what the power does) and trace the wires along the route to the transfer switch. At least you are starting with the right wires.

We likely have only 3 scenarios here. The Generator is no longer producing power. The transfer switch has failed. There is a tripped circuit breaker.

At this point the two easiest to rule out are the transfer switch and the generator. A multimeter can rule out both items quickly.

Start the generator and test it with the multimeter. It either has voltage or it doesn’t.

With the transfer switch we need to rule out several possibilities. Leave the generator running. Unplug shore power. Move the switch to generator. Test for voltage in. No voltage problem isn’t the switch. If there is voltage in then test for voltage out. We already know there is no voltage out but test anyway. If no voltage then the switch needs to be replaced. If you don’t know what is in or out just test all three. If you have voltage on only one leg it’s the switch. If you have voltage on two legs or no legs the problem is some where else.

I have seen these switches fail such that you can switch sources but internally the circuit can not be completed.

luna said:

How would a layman know which of the wires connected to the transfer switch actually go to the Genset? You have a 50% chance of getting it right, if there is also just a shore power connection.
Start at the Genset (thats what the power does) and trace the wires along the route to the transfer switch. At least you are starting with the right wires.

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I don’t know? Maybe a continuity test? Sounds a hell of a lot easier than following wires. Would also let you know if there was a circuit breaker issue in the wire.

My comment was really directed at Daniel who suggested to start at the transfer switch and trace wires to the Genset. Why?

I agree that following wires could be difficult and a continuity test may prove useful, but you nor I know the skill set of the OP.
To suggest that the next thing to do is to start probing for voltage at the Genset or switch could prove dangerous.

Following wires with the Genset off is much more harmless.

luna said:

My comment was really directed at Daniel who suggested to start at the transfer switch and trace wires to the Genset. Why?

I agree that following wires could be difficult and a continuity test may prove useful, but you nor I know the skill set of the OP.
To suggest that the next thing to do is to start probing for voltage at the Genset or switch could prove dangerous.

Following wires with the Genset off is much more harmless.

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Thank you for your input people. I had a guy use a multimeter and he says no power coming out of the generator control box. He is suggesting the alternator or the voltage regulator is bad and he is not an Onan repairman. So I need to find the voltage regulator as I can see the alternator at the front of the generator where the belt goes around it. Where is the voltage regulator?

? I thought it was the AC power problem. Regulator and Alternator are DC current to charge the battery.

Alternators (your engine mounted, belt driven alternator or the alternator mounted directly to the Genset’s engine) produce only alternating current. That’s what rotary current machines do.
From there the wave form could be rectified into what could pass as dc to a battery.
That happens inside your car’s alternator, but not in a Genset's large directly coupled alternator generally, as we in this instance are really looking for the ac.

As Daniel a few posts ago indicated that he has the shop manual perhaps he will advise as to the location of the voltage regulator.

luna said:

I'm not sure of what exactly happened.

To the OP, does the Kubota D950 3 cylinder diesel engine that likely powers the Genset still run or is it dead and won't start?

Do you know if you have any 240 Volt consumers onboard, maybe a water heater, range, or clothes dryer?

The wires that carry the output from the Genset are about the diameter of an Eagle HB wood pencil, remember those from grade school?

If you have traced those sized wires from the Genset to a switch or load panel and found no breakers, first I'm surprised and 2nd, you have more work to do.

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The gentleman that tested the with the multimeter there is no power coming off the Gen Set itself while it was running. He mentioned it might be the alternator or the voltage regulator. I can see where the alternator is, but I cannot find the voltage regulator??

SteveK said:

? I thought it was the AC power problem. Regulator and Alternator are DC current to charge the battery.

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The man checked with his multimeter and found that no power is coming from the generator while it was running. What could be the problem? The alternator or where is the voltage regulator on the Gen Set?

SteveK said:

The GEN was running, and then quit. That made it sound like a breaker.
But, I have had a failed transfer switch.
An electrician is needed to tap into the AC power lines from GEN to see if GEN is out putting.

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The Gen Set is not out putting. Now I need to find the source of the problem?

Generator has a stator and a rotor for AC current. The Alternator and regulator is DC with the sole purpose of recharging the generators battery.

I am unable to tell if you tested the wrong part or if you are using the wrong terminology.

Since you didn’t test at the transfer switch I am guessing the guy with the multimeter really doesn’t have a clue what to test.

tiltrider1 said:

Generator has a stator and a rotor for AC current. The Alternator and regulator is DC with the sole purpose of recharging the generators battery.

I am unable to tell if you tested the wrong part or if you are using the wrong terminology.

Since you didn’t test at the transfer switch I am guessing the guy with the multimeter really doesn’t have a clue what to test.

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that may be true as he said to contact the Onan dealership. I am afraid to get cheated? I have another electrician boat repairman on the way now. Pray to tell I will get some results.

Destiny of the Sea said:

that may be true as he said to contact the Onan dealership. I am afraid to get cheated? I have another electrician boat repairman on the way now. Pray to tell I will get some results.

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There was no need to test the transfer switch as generator was not out putting power. correct?

Destiny of the Sea said:

There was no need to test the transfer switch as generator was not out putting power. correct?

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But I will ask him to do the test on the transfer switch anyway for the sake of the arguement

Let's see if I can clear things up a bit as the terminology can get confusing.

Your Genset is powered by a diesel engine and just like the engine in your car it has mounted on it a belt driven Alternator (about the size of a grapefruit) who's sole purpose in life is to charge the start battery and keep whatever primitive electronics powered so if there is an engine fault, you know about it. This Alternator like all alternators produces alternating current (thats all they can produce and why they are called Alternators) except that in this instance it is converted (rectified) to a form of alternating current that a direct current (there is no other kind) battery will find useful. We call the output from this alternator dc but if you look at the actual wave form it has an ac ripple to it just like the wave form from your ac powered battery charger. Regardless, the battery can accept this almost dc just fine, so all is good.
This small alternator on my MDKD is a permanent magnet alternator and as a result there is no field coil to control with a voltage regulator, so as logic would dictate, there is no voltage regulator. What would be the point? The alternator just puts out about 8 Amps at 1800 RPM and that has kept the 8+/- year useable lifespan of the batteries in a charged state for now 28 years. Barring alternator failure, I don't expect that to change.

This small alternator is not responsible for your current difficulties, so let's not talk about it anymore, Ok?

Your Genset has another alternator, although some people call it a generator end, it's really an alternator so let's call it what it is. Also, that is what the manufacturers of this thing call it, so good enough for me.
This time this alternator is about the size of a 5 Gallon bucket and it's directly mounted horizontally at the end of the engine that does not have the fan belt on it. (Notice I didn't reference the small alternator!) This alternator's job is to produce the ac power that you will use to make coffee, nuke your pizza, heat the water, etc. I trust this is the alternator that your electrical friend had measured and unfortunately found no output. There is at least handful of reasons why there is no output from the alternator.
One of those reasons could be a failed voltage regulator (yep, this alternator has one) but sadly the last time I looked this VR is long out of production and the OEM one is likely unobtainable. How to test if it still works requires a better understanding of how it works and some sophisticated test equipment that I'm sure you don't have.
The best you could likely do is to find the 30 Amp, 32 Volt Slo Blo AGC glass inline fuse that likely is in the power line to the VR and see if it is still intact. Replace it if it has failed and fire the thing up with your fingers crossed.
I think a firm called Flight Systems Inc. might be able to provide a VR replacement. They may also be able to test your original VR. Would you trust their findings understanding that they may sell new ones?

Here is their link. Good luck!


Oh, before I forget, the voltage regulator for the larger alternator is mounted on upper right corner of the baffle that is visible once you take the cover off of the alternator end of the sound shield. It's clearly visible as the finned component in the 2nd picture of your post #13.

I thank you all for your support. It was a faulty voltage regulator. I have a new one coming from the factory in a couple of days. I cannot wait to have this installed and be back on the water! Steve

How did you diagnose the VR as the culprit and where did you get the replacement VR from?

Just would like to know so that when mine goes, some of the leg work is already done.

Thanks.