# Westinghouse WPro8500 - Tri-Fuel Conversion



## ddbama (Aug 3, 2021)

Has anyone converted a WPro8500 to natural gas using a motor snorkel or other tri-fuel conversion kit? Any tips/tricks on installing a conversion kit on this specific generator? Does the autochoke need to be disabled or any other specific items on this generator need to be modified outside of the typical conversion kit installation instructions? I have installed a motor snorkel on my WPro8500 and everything seems to be functioning normally except the generator RPMs seem to be fluctuating up and down (surge up and down) while the generator is running on natural gas. Load block settings do not seem to impact this fluctuation of RPMs.


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## ToolLover (Jan 13, 2020)

Your problem sounds like a pressure regulator problem or feed line problem.
A steady flow of NG would not cause fluctuations in speed.
Test the supply for 5 to 7 Inches of H2o at the generator first as a starting point.
Find a gauge on Amazon for testing.
*Measureman Natural Gas or LP Gas Manifold Pressure Test Kit, 0-35 "W.C., 1/4"NPT, 40" Length Hose*


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## ddbama (Aug 3, 2021)

Thanks for the reply. My natural gas service supply regulator is 7" H2O going into meter. The piping from the meter is 1" and my generator connection is a 3/4" tee, 3/4" full port valve, 3/4" quick connect, and 20 ft x 3/4" hose. Outside of having the test gauge to verify the supply pressure, is there anything else in my setup or other adjustments I need to make to the generator (such as disabling the autochoke)? According to motorsnorkel the 3/4" connections should be sufficient for this generator size and the motorsnorkel kit only requires 4"-8" H20 supply pressure.


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## iowagold (Jan 22, 2020)

there could be an issue of a bad demand regulator.
it needs the signal to be just right to trip the demand regulator to flow....
or it can be the suction on the snorkle setup.
buy the correct wc meter to check this... my $600 dollar digital unit does pressure as well as suction.
the line from the snorkle needs to have no or limited bends in the hose radius.
that will keep the suction signal right.


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## iowagold (Jan 22, 2020)

oh yea did you change the spark gap to sae 20 thou?
and are you using the iridium spark plug?


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## ddbama (Aug 3, 2021)

I'm currently using an iridium spark plug. The hose from the snorkel to the regulator has limited bends (I placed the regulator on the upper frame in the same position shown on a similar Westinghouse generator conversion US Carb has on the instructional video on their website). Can the carbon canister and/or auto choke (both included on the WPro 8500) have an impact on running the generator on natural gas? It will take a few days to get a meter so attempting to troubleshoot if there are any other items I should check / modify. The generator is running on natural gas and supplying electrical power. There is just a cyclical rpm fluctuation that I don't notice when running on regular gas.


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## Jackruf (Nov 4, 2012)

ddbama said:


> I'm currently using an iridium spark plug. The hose from the snorkel to the regulator has limited bends (I placed the regulator on the upper frame in the same position shown on a similar Westinghouse generator conversion US Carb has on the instructional video on their website). Can the carbon canister and/or auto choke (both included on the WPro 8500) have an impact on running the generator on natural gas? It will take a few days to get a meter so attempting to troubleshoot if there are any other items I should check / modify. The generator is running on natural gas and supplying electrical power. There is just a cyclical rpm fluctuation that I don't notice when running on regular gas.


Disable the auto choke - it needs to be in open position.


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## ddbama (Aug 3, 2021)

What is the best way to disable the autochoke on the WPro8500?


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## tabora (Sep 6, 2018)

ddbama said:


> What is the best way to disable the autochoke on the WPro8500?


From the wiring diagram, it looks like you just have to unplug the connection I've circled in red:


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## iowagold (Jan 22, 2020)

unless the start up self check does not like that..
some modern gens will not run if sensors etc are just unplugged.
try it unplugged and wire it or zip tie it open.


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## Jackruf (Nov 4, 2012)

ddbama said:


> What is the best way to disable the autochoke on the WPro8500?


The Honda EU Series have a connector on the carb that you can carefully unplug to disable the autochoke. You can then manually move the lever to the open position. Hopefully your unit has a similar set up. Best of luck with it.


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## ddbama (Aug 3, 2021)

Disabled the autochoke and not seeing any noticeable difference in performance. Generator runs smooth when unloaded (no major fluctuations). I did observe the fuel stepping motor adjusting every time the fluctuations occurred. The output voltage & frequency would drop as the engine sounded bogged down, the fuel stepper motor would adjust and the voltage & frequency would climb, then the fuel stepper motor would adjust again causing the voltage & frequency to drop until the cycle repeats again.


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## iowagold (Jan 22, 2020)

hummm...
450cc engine.....
what gauges do you have?
you need to watch the demand regulator on the feed and the output to get an idea of what is up on the flow...

do you have a load block on top of the demand reg?
if so what is the feed hose ID?
snap a few pix for us...
make sure the hoses are strait on the feed from the demand regulator to the carb plate..
also there could be an issue with the plate flow...


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## ddbama (Aug 3, 2021)

x


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## iowagold (Jan 22, 2020)

hummm
looks to be over tight on the air filter housing bolts?
it might be pinching the feed...
or is the plate made on an angle?


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## ddbama (Aug 3, 2021)

x


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## ddbama (Aug 3, 2021)

The picture may have been misleading. The motorsnorkel has a flat section built into the "gasket"


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## iowagold (Jan 22, 2020)

snap a pix side ways of the plate
is the plate/gasket even thick 360 deg?
in the gen photo it looked smashed out...


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## ddbama (Aug 3, 2021)

Finally got some time to test run the generator today. I think I finally tracked down the problem to the hair dryer I was using as a test load (120V outlet). I decided to test the generator on regular gas and when this hair dryer was plugged in the generator did the same “surging” / hunting for the right throttle/engine speed. So I unplugged the hair dryer and tried a different dryer and vacuum and the generator ran perfect. Then proceeded to hook the generator back up to my natural gas supply and tested with different loads (120V) and had no issues or surging like I got with the original hair dryer connected. I then hooked up the generator to the house through my 240v 50amp inlet and was able to run all of my essential loads including my 3 ton hvac off of the natural gas supply and again confirmed no issues. So it seems my problem was this one hair dryer and not the snorkel/regulator/natural gas supply. Thank you all for your assistance while I was attempting to troubleshoot this issue. Never expected the test load (hair dryer) to be the issue.


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## iowagold (Jan 22, 2020)

lol
yea test the test equipment!
GRIN!
glad you are up and running!
yea it is exciting when it all works out!
make sure to break in proper
and do your pm's (oil and air filter changes ) on the marks.


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## ddbama (Aug 3, 2021)

Thanks! Ran the generator 3.5 hrs on regular gas before converting to natural gas (read 2 hr minimum for break in) and have all the maintenance supplies I need to stay operational for a > 1 week outage.

not sure what’s wrong with the hair dryer I was using as a test load, but glad I found the problem. When connected to my house the generator was able to hold a constant supply voltage and frequency under load.


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## iowagold (Jan 22, 2020)

yea could be a crazy inductance thing


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## drmerdp (Apr 10, 2018)

Really strange. For the most part blow dryers are a simple resistive load minus the fan. I wonder if there is something funny with the GFI on the plug.


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