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Onan 4.0CCK round style generator head


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  #31  
Old 03-15-2017, 06:37:19 PM
Kevin K Kevin K is offline
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Default Re: Onan 4.0CCK round style generator head

Let's review the current situation:
Your CCK is running at 1800RPM, approximately 60Hz.
The AC voltage output is in the area of 125 volts no load.
The CCK can handle a full 4,000 watts load, with the AC voltage output in the area of 110 volts at full load.

I looked in the database, but I can't find a production order for 4.0cck-1r/111p. Our database is not perfect, and there are occasionally models that do not show up. I did find 4.0CCK-1R/11191P, is this your number?

With an exciter voltage of approximately 17 volts, there may be nothing wrong with your generator. The exciter voltage is proportional to engine speed. If the exciter voltage was approximately 1/2 of normal, there is no way the generator could produce full output. The Onan regulation scheme on these generators is to magnetically saturate the pole pieces so that the output voltage is proportional to engine speed.

Onan does not seem to specify exciter voltage on the round head CCK's. The square head UN generator ends, including the CCK's, run at approximately 30 VDC. The MCCK's, both round and square head, run at approximately 30VDC except for Spec H which runs at 110VDC.

The 2.5LK exciter voltage runs at 17VDC, except for the "utility truck" model which runs at 15VDC.

I'm not sure about the round head CCK's. I think some run at lower voltages than 30VDC, but I'm not sure which ones, and I'm not sure of the voltage. I have a 4.0CCK-3CR and a 5.0CCK-1R round head CCK's, but they are sitting up on blocks in the basement and I can't easily get them out until summer.

Maybe someone with a round head 4CCK can measure the exciter voltage.

I would say that if your 4CCK is running at 1800RPM (60Hz), the no load voltage is correct, and it can carry a full load the exciter voltage is OK.
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  #32  
Old 03-16-2017, 12:24:05 AM
turtmaster turtmaster is offline
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Default Re: Onan 4.0CCK round style generator head

Kevin, yes 11191p is correct, I thought that the number was wrong, but I could not check it as the gen is at my dad's house, I can't find off-hand what the number for the bimetallic choke spring that I used, it was the only number I could find in several of the cck parts manuals, in several of the part manuals, the number for the choke coil spring was BLANK in the spot for it, from the one on the twinslan site. The smaller several turn coil is the new one, the older larger 15+ turn coil in the hand is the old coil, was SPRUNG, but the new coil is the only cck choke coil spring part I could find. The reason I was asking about the choke's excited voltage being low, is that was taking FOREVER for the choke to open, compared to my other spec r 4.0 square head cck that I converted from the "sisson" type choke to the "Onan" type choke,and carb that I got from spenserpearson's bf that he was parting out. And also compared to my 5.0 bga, it was taking FOREVER for the choke to open, like 5 minutes for it to fully open. So that's when I checked the excited voltage, and found it was only 17.5v.

When you look at the picture of the choke spring in the choke housing, the old choke spring left marks on the back of the choke housing that look like a spring.


Could the commutator brush holder assembly "clock/clocking" position have something to do with the low exciter voltage?

I am almost tempted to order a cheap $10 5-10a dc-dc boost converter from the Asian country that starts with the letter "C" from eBay for a quick fix to get the choke to open faster.
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  #33  
Old 03-16-2017, 01:55:15 PM
Kevin K Kevin K is offline
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Default Re: Onan 4.0CCK round style generator head

Quote:
Originally Posted by turtmaster View Post
Could the commutator brush holder assembly "clock/clocking" position have something to do with the low exciter voltage?
You don't want to mess with that adjustment if the generator is working correctly. Finding the neutral point has been discussed somewhere here in the past. Changing the adjustment can lead to excessive sparking on the commutator brushes.

I looked at the choke heater in a few of my generators, as well as searching through some parts manuals. The parts manuals all reference the same number 153-0017 (153-A17). One LK, a BFA, and a square head CCK had the small spring. My round head 5CCK had the larger spring. I think the springs work the same, the smaller version is the newer replacement.

There is a difference in the choke heater. The generators with the 17 volt exciter (2.5LK, 5CCK round head) use part number 153-0113, which measures approximately 11 ohms. The generators with a 28 to 30 volt exciter (5CCK square head, 4BFA) use part number 153-0114, which measures approximately 28 ohms.

Check your heater to see which version you have. For your 17 volt exciter you need 153-0113. Using the 153-0014 would cause the choke to open very slowly.

We both learned something here. There is a difference in the exciter voltage between the round head and square head CCK models. There are two different choke heater elements available for use with the lower 17 volt and higher 28 volt exciters.
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  #34  
Old 03-16-2017, 09:21:58 PM
turtmaster turtmaster is offline
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Default Re: Onan 4.0CCK round style generator head

I Called my dad and had him measure the resistance of the choke heater and it is 10 ohms, the part number on the choke heater is 153-113 in the old part numbering system, so the new system part number is 153-0113 so I guess we now know that round head cck generator heads have 17v exciter choke heater voltage instead of the un heads 30v exciter voltage.
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  #35  
Old 03-17-2017, 06:57:13 AM
Kevin K Kevin K is offline
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Default Re: Onan 4.0CCK round style generator head

So then, why the slow choke opening? The 2.5LK I checked, made in 1987, has the small spring and the 153-0113 heater. Because it is a "Utility Truck" model, the exciter voltage is 15 volts, lower than the standard 17 volts, Yet the choke works well.

Did you set the initial choke opening based on ambient temperature? The choke should not be fully closed unless the ambient temperature is below 50 degrees or so. The Master Engine Service Manual has a chart with a guide to setting the initial opening.
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  #36  
Old 03-17-2017, 02:51:24 PM
turtmaster turtmaster is offline
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Default Re: Onan 4.0CCK round style generator head

Kevin, I had the furnace in the garage set to 58° F when I was assembling and adjusting the choke, and yes I looked up the choke adjustment info from the twinslan site that I had previously downloaded, and adjusting it to what it said. then I took the gen outside to test run it, the only thing I can otherwise think of why it was taking so long to open up is that was only about 25° F outside at the time of the generator test run.

And I had let the generator cold soak outside for a little while.
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  #37  
Old 03-17-2017, 03:54:58 PM
Kevin K Kevin K is offline
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Default Re: Onan 4.0CCK round style generator head

OK, I admit I never started my CCK's at that low of a temperature. I guess that's what I can expect. The manuals mention adjusting the choke for different temperature conditions. We just let it warm up for five minutes or so.

The newer sets such as the Emerald have a vacuum pull-off to open the choke a bit when the engine has started.
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