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Onan 12.5JC Sorting it Out


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  #21  
Old 02-09-2018, 12:37:22 AM
JohnnyC JohnnyC is offline
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Default Re: Onan 12.5JC Sorting it Out

Okay, your carb is looking good... I attached 4 pictures below showing the internals of my tri-fuel carburetor. I hope this will help you to know what you have and what you need to find to convert your carb to tri-fuel. It took a few minutes to dig up my pictures, but I knew I had detailed pictures from when I rebuilt my tri-fuel carburetor. I got pictures of everything I do. Seriously, I will snap thousands of pics, but sometimes it take a very minutes to find them.

JohnnyC
New Jersey
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  #22  
Old 02-09-2018, 12:44:47 AM
consolenut consolenut is offline
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Default Re: Onan 12.5JC Sorting it Out

Looka likeni need the float assembly and the pin etc that retains it. Also the main jet or seat thatvthreads in the bottom og the carb. Everything else is there. I believe this kit i fohbd has what im lackin parts wise.
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  #23  
Old 02-09-2018, 09:30:48 AM
stretch67 stretch67 is offline
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Default Re: Onan 12.5JC Sorting it Out

My 1975 JC is setup for gaseous only and has all 3 screws on the top of the Carburetor

Many have looked for the TRI FUEL carburetor and few have found.

Kind of a rare item these days.

If you have NG or Propane handy its better to run her off that.

This may be what your looking for but smarter people then me will know better.
https://www.ebay.com/itm/Carburetor-...AAAOSwud1XAkMp
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  #24  
Old 02-09-2018, 01:12:14 PM
consolenut consolenut is offline
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Default Re: Onan 12.5JC Sorting it Out

Not really.interested in tri fuel. I will run it on gasoline.. Non ethanol gas is easy to get here. And it will be run atleast two or three times a month. Minimum!
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  #25  
Old 02-09-2018, 04:18:30 PM
stretch67 stretch67 is offline
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Default Re: Onan 12.5JC Sorting it Out

Now i did watch a Engine Masters show the other day and they did a test with E85 and 114 Race fuel.
Big block Chevy Engine. 13 to 1 compression ratio I think.
HP wise the same torque wise bit different.

Neat thing on gas not a street driving motor due to the race gas.
On E85 no problem with street use. Just a lot less range in your tank.
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  #26  
Old 02-09-2018, 06:35:44 PM
Viking66 Viking66 is offline
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Default Re: Onan 12.5JC Sorting it Out

If you have Nat Gas that is the best way to go.

Waiting in line for gas, especially the amount a JC will need is not a fun prospect...Just Saying
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  #27  
Old 02-09-2018, 06:39:04 PM
JT240Z JT240Z is offline
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Default Re: Onan 12.5JC Sorting it Out

Quote:
Originally Posted by stretch67 View Post
Now i did watch a Engine Masters show the other day and they did a test with E85 and 114 Race fuel.
Big block Chevy Engine. 13 to 1 compression ratio I think.
HP wise the same torque wise bit different.

Neat thing on gas not a street driving motor due to the race gas.
On E85 no problem with street use. Just a lot less range in your tank.
E85 suffers water absorption problems throughout the fuel system. Wouldn't put it into anything. Even if it's designed for it. Bad idea from the start.
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  #28  
Old 02-09-2018, 07:30:11 PM
consolenut consolenut is offline
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Default Re: Onan 12.5JC Sorting it Out

My JC is mobile. Its going in the back of my.medium duty truck. Its almost there. I got itnrunning on a borrowed regulator today to check it out. As soon as the videos upload ill share
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  #29  
Old 02-09-2018, 07:40:01 PM
JoeE. JoeE. is offline
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Default Re: Onan 12.5JC Sorting it Out

The lowest price I found on one of those low pressure fuel pumps was about $35... online.

https://aftermark.net/fep04sv-facet-...tallation-kit/
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  #30  
Old 02-09-2018, 08:50:09 PM
consolenut consolenut is offline
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Default Re: Onan 12.5JC Sorting it Out

https://youtu.be/vDnRFuqg4KQ

Quick vid running on prpoane. Ive got it reconnected single phase 220. In the video you can the voltage is rock.steady.

---------- Post added at 08:25:41 PM ---------- Previous post was at 08:24:17 PM ----------

Has a steady 30psi of oil pressure. I was surprised it was that good.

---------- Post added at 08:50:09 PM ---------- Previous post was at 08:25:41 PM ----------

The twinslan aite is down it appears. Does anyone have the parta and owners manual for this JC.....spec AB.
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