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propane/natuural gas on generator

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Posted by clare on November 21, 2015, 6:57 am
I have a 7200/9000 watt Champion generator with a US Carb motor
snorkel conversion that is not putting out anywhere near full power
and is tricky to start. I suspect the pikot ajustment? is not correct
(the spring adjustment screw under the plug above the fuel inlet on
the Century zero regulator unit.
Anyone know the best way to determine the proper adjustment? I know
they are VERY fussy and turning the screw in makes it go lean. (more
intake vacuum required to open the valve)

 I was getting 4500-5300 watts out of the 7200 watt unit, which is low
( should get 6400-6500 watts)

Posted by Vaughn Simon on November 21, 2015, 12:34 pm
On 11/21/2015 1:57 AM, clare@snyder.on.ca wrote:

Hopefully someone will come along with more experience than I.  But I  
will try to get this conversation started

You haven't mentioned trying the mixture adjustment, which should be  
separate from the adjustment on the zero regulator.

Very basic, is fuel pressure.  You should find the specification with  
the conversion kit.  It is measured in inches of water.   You can buy a  
gauge, or make your own manometer from some clear tubing and a yardstick  
like I did.  You may find that your fuel pressure under load goes too  
low.  That could be anything from a simple fuel regulator adjustment, to  
the need for a larger (or more direct) fuel supply line.  There should  
be measurement ports for both the inlet and outlet of your zero regulator.

I have had the same zero regulator since my ancient Onan was factory  
new, and don't remember ever adjusting it.  My mixture adjustment  
however, is another matter.


Posted by clare on November 21, 2015, 4:08 pm
 On Sat, 21 Nov 2015 07:34:16 -0500, Vaughn Simon

 The only "mixture adjustment" is the load block. Full range of
adjustment there only made things worse, not better, as far as power
output. The natural gas pressure is regulated by the utility - New
meter and regulator installed this summer - all to spec. Same problem
exists on Propane with regulator supplied by US Carburetor - and 2
regulators behave exactly the same.

2 identical generators with the same issue. Run fine on Gasoline. If
anything it acts like the generator is running too rich under full
load - it loads up and takes time to clear after the load is removed
(if I catch it before it dies)

Posted by Vaughn Simon on November 21, 2015, 6:59 pm
 On 11/21/2015 11:08 AM, clare@snyder.on.ca wrote:

Regardless of the above, you haven't even begin to troubleshoot this  
problem until you have checked gas pressures at the test ports UNDER  
LOAD to see if they meet specifications.  Your description sounds very  
much like you aren't getting sufficient fuel pressure to the regulator.  
  Particularly telling is the fact that you had the same symptom with  
two generators.

My brother recently had curious symptoms with his gas oven.  After much  
head scratching he finally checked his fuel pressure under load. He  
found an obstruction a gas line that looked perfectly good from the  

Posted by clare on November 21, 2015, 8:31 pm
 On Sat, 21 Nov 2015 13:59:07 -0500, Vaughn Simon

 When on both natural gas and propane, on 2 generators, and 2 propane
regulators, and 4 propane tanks (2 at a time on each generator) I have
the same problem.(actually, the second generator has never been run on
natural gas) The natural gas pressure has been verified.7.5"wc at the
quick connect  with furnace and water heater both running . Have not
verified the propane pressure, but the regulators were both supplied
by US CArburetor for the application. Pressure has not been verified
at the zero regulator.

 And regardless, NO-ONE has answered my question on how to adjust the
spring pressure on the Century Zero Regulator - or even what the
effect of pilot vacuum being higher or lower than spec would be.

I've googled it all kinds of ways and have found nothing.

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