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Voltage too high on my Onan 4.0 BFG /1r


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Old 02-15-2014, 10:01:39 PM
tdarden tdarden is offline
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Default Voltage too high on my Onan 4.0 BFG /1r

This was the second Onan that I bought. Never got it to run very well because I determined that it needed a carb rebuild so I decided to propane it.
Got started with it over the weekend and got it running pretty well. My problem is the voltage at no load is about 128-129 and that is as low as it will go. I am using a drilled carb and I RTV'd all the holes and orifices. I am using a decent meter as I brought it into the house and was getting 121v.

I was using a Propane Carburetion's load block but I just didn't like it so I went with a WOG ball valve . The load block gets you started quicker from scratch but I struggled adjusting it. Any thoughts on what my issue could be?

I would love to have a no load voltage of 125-126 .... Thanks
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Old 02-15-2014, 10:09:42 PM
yellowlister yellowlister is offline
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Default Re: Voltage too high on my Onan 4.0 BFG /1r

if I remember right 128-131 volts unloaded is normal.. whats the hertz when your getting 128 volts? what about when you load it up?
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Old 02-15-2014, 10:13:57 PM
tdarden tdarden is offline
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Default Re: Voltage too high on my Onan 4.0 BFG /1r

Hmmmm That would be great then. Unfortunately I don't have a frequency meter yet but I will be getting one soon.
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Old 02-15-2014, 10:33:33 PM
yellowlister yellowlister is offline
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Default Re: Voltage too high on my Onan 4.0 BFG /1r

just looked at the factory manual. max No load is 132volts 63 hertz at 1890 rpm,. minimum full load voltage of 108v 57 hertz at 1770 rpm per the manual for a single phase 120 2 wire gen

it says with the unit warmed up at No load adjust it to 127 volts and 61 hertz.. by adjusting the tension of the governor spring
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Old 02-15-2014, 10:48:59 PM
tdarden tdarden is offline
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Default Re: Voltage too high on my Onan 4.0 BFG /1r

Thanks yellowlister. Went looking for my service manual and only had the parts manual. If you would be so kind and have it in electronic form, would you send a copy to wxyoung2008@gmail.com
Thanks
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Old 02-15-2014, 11:05:39 PM
len k len k is offline
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Default Re: Voltage too high on my Onan 4.0 BFG /1r

To measure hz can plug 120VAC mechanic clock into gen and compare time to another clock. If gen clock is 2 seconds fast in one minute, gen is 62hz not 60. Can measure over more than one minute for better accuracy.

Many people here use a killawatt meter for HZ. I was thinking of getting their model P4400 , direct push button access to changing display vs having to go thru a menu. On ebay there's a Hackensack, N. J. company that keeps selling them, wining bid is usually about $13-14 lately plus ~3 shipping.

Plus the meter displays TRUE RMS volts, amps........ and power factor.

Last edited by len k; 02-15-2014 at 11:55:20 PM. Reason: spelling,,,,2 seconds fast in one minute,,,,,, TRUE RMS
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Old 02-15-2014, 11:16:03 PM
tdarden tdarden is offline
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Default Re: Voltage too high on my Onan 4.0 BFG /1r

Quote:
Originally Posted by len k View Post
To measure hz can plug 120VAC mechanic clock into gen and compare time to another clock. If gen clock is 2 seconds fast, gen is 62hz not 60. Can measure over more than one minute for better accuracy.

Many people here use a killawatt meter for HZ. I was thinking of getting their model P4400 , direct access to changing display vs having to go thru a menu. On ebay there's a Hackensack, N. J. company that keeps selling them, wining bid is usually about $13-14 plus ~3 shipping

Thanks Len K
Sounds like both a cheap and a free way to check frequency. I will go and search for one now. Thanks again
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Old 02-15-2014, 11:18:04 PM
len k len k is offline
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Default Re: Voltage too high on my Onan 4.0 BFG /1r

This is the ebay seller I was talking about, Seller: discountaudiowarehouse


http://www.ebay.com/itm/P3-KILL-A-WA...ht_5149wt_1003
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Old 02-16-2014, 12:36:02 AM
yellowlister yellowlister is offline
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Default Re: Voltage too high on my Onan 4.0 BFG /1r

manual should be in your box
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