Generators and Motors
[Home] - [HELP] - [Forums] - [Library] - [Photo Gallery] - [Groups] - [Classified Ads] - [Subscribe] - [Links] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Vintage Electrical Equipment > Generators & Electric Motors General Discussion > Onan Generators
Forgot Password? Join Us!

Notices

Onan Generators Restoring, operating and maintaining vintage Onan generators.

Onan Generators

Onan 12.5JC Sorting it Out


this thread has 77 replies and has been viewed 2306 times

Reply
 
Thread Tools Display Modes
  #11  
Old 02-08-2018, 11:58:22 PM
consolenut consolenut is offline
Registered-I
 
Join Date: Oct 2017
Location: Bristol, Tennessee / Broken Arrow, Oklahoma
Posts: 305
Thanks: 16
Thanked 75 Times in 59 Posts
Default Re: Onan 12.5JC Sorting it Out

Carb picture
Attached Thumbnails
Click image for larger version

Name:	IMG_20180208_215255.jpg
Views:	40
Size:	78.3 KB
ID:	302696  
Reply With Quote
Sponsored Links
  #12  
Old 02-09-2018, 12:00:48 AM
consolenut consolenut is offline
Registered-I
 
Join Date: Oct 2017
Location: Bristol, Tennessee / Broken Arrow, Oklahoma
Posts: 305
Thanks: 16
Thanked 75 Times in 59 Posts
Default Re: Onan 12.5JC Sorting it Out

Yeah i was planning an electric fuel pump.. If i can find a gas carb on ebay ill go that route. The oil was squeaky clean in it. And ill get the tune parts in the mean time. Aa i know using that big hose thats nornally for a propane line. Is not wise to draw gasolibe through.
Reply With Quote
  #13  
Old 02-09-2018, 12:03:43 AM
JohnnyC JohnnyC is offline
Subscriber
 
Join Date: Jun 2014
Location: Boonton, New Jersey
Posts: 4,702
Thanks: 1,602
Thanked 2,318 Times in 1,346 Posts
Default Re: Onan 12.5JC Sorting it Out

Does your carburetor have the two small needle valves as seen in the picture below? I'm not sure if a gas only carburetor only has one and the other plugged???? I'd have to dig up some pictures from my 15.0JC refurb which had a gaseous carb.

JohnnyC
New Jersey
Attached Thumbnails
Click image for larger version

Name:	001.jpg
Views:	34
Size:	127.8 KB
ID:	302697  
Reply With Quote
The Following User Says Thank You to JohnnyC For This Post:
  #14  
Old 02-09-2018, 12:08:45 AM
consolenut consolenut is offline
Registered-I
 
Join Date: Oct 2017
Location: Bristol, Tennessee / Broken Arrow, Oklahoma
Posts: 305
Thanks: 16
Thanked 75 Times in 59 Posts
Default Re: Onan 12.5JC Sorting it Out

Yeah i was planning an electric fuel pump.. If i can find a gas carb on ebay ill go that route. The oil was squeaky clean in it. And ill get the tune parts in the mean time. As i know using that big hose thats nornally for a propane line. Is not wise to draw gasoline through.

---------- Post added at 12:08:45 AM ---------- Previous post was at 12:07:10 AM ----------

Yea it has the two needle valves on top and the larger one in the middle. Same as yours
Reply With Quote
  #15  
Old 02-09-2018, 12:10:55 AM
JohnnyC JohnnyC is offline
Subscriber
 
Join Date: Jun 2014
Location: Boonton, New Jersey
Posts: 4,702
Thanks: 1,602
Thanked 2,318 Times in 1,346 Posts
Default Re: Onan 12.5JC Sorting it Out

As I thought.... Look at the picture below of a gaseous carb from my 15.0JC and notice that one of the smaller needle valves is missing. Check and see if yours is plugged and if it is, I wonder if the bore is threaded or not..
Attached Thumbnails
Click image for larger version

Name:	001.jpg
Views:	36
Size:	210.0 KB
ID:	302698  
Reply With Quote
  #16  
Old 02-09-2018, 12:13:16 AM
JohnnyC JohnnyC is offline
Subscriber
 
Join Date: Jun 2014
Location: Boonton, New Jersey
Posts: 4,702
Thanks: 1,602
Thanked 2,318 Times in 1,346 Posts
Default Re: Onan 12.5JC Sorting it Out

OK, I think we both posted at roughly the same time.... As you can see, my gaseous 15.0JC is missing one of the smaller needle valves and yours is not.. That's good. Are you sure yours does not have a float?

JohnnyC
New Jersey
Reply With Quote
  #17  
Old 02-09-2018, 12:13:49 AM
consolenut consolenut is offline
Registered-I
 
Join Date: Oct 2017
Location: Bristol, Tennessee / Broken Arrow, Oklahoma
Posts: 305
Thanks: 16
Thanked 75 Times in 59 Posts
Default Re: Onan 12.5JC Sorting it Out

There are the needle and seat you ask about. And the pickup tube where the needle and seat id assume threaded into in the bottom the carb isbthere as well. As inseen it when i took the bowl off.
Attached Thumbnails
Click image for larger version

Name:	IMG_20180208_221043.jpg
Views:	32
Size:	90.1 KB
ID:	302699  
Reply With Quote
The Following User Says Thank You to consolenut For This Post:
  #18  
Old 02-09-2018, 12:17:59 AM
JohnnyC JohnnyC is offline
Subscriber
 
Join Date: Jun 2014
Location: Boonton, New Jersey
Posts: 4,702
Thanks: 1,602
Thanked 2,318 Times in 1,346 Posts
Default Re: Onan 12.5JC Sorting it Out

.... just to confirm that my gaseous carb from my 15.0JC does NOT have the third needle valve I attached several more pictures below from a different view. FWIW - not to confuse the idle stop as the needle valve in my pics below. Looks like my third is plugged.

JohnnyC
New Jersey
Attached Thumbnails
Click image for larger version

Name:	001.jpg
Views:	31
Size:	220.8 KB
ID:	302700   Click image for larger version

Name:	002.jpg
Views:	29
Size:	153.5 KB
ID:	302701  
Reply With Quote
  #19  
Old 02-09-2018, 12:22:41 AM
JohnnyC JohnnyC is offline
Subscriber
 
Join Date: Jun 2014
Location: Boonton, New Jersey
Posts: 4,702
Thanks: 1,602
Thanked 2,318 Times in 1,346 Posts
Default Re: Onan 12.5JC Sorting it Out

Try to find a gasoline junk carb on FleaBay and transfer the missing parts for gasoline to your gaseous carb. Hopefully that is all you may need. Also make sure that the float needle seat in the body of your gaseous carb is threaded to accept a needle seat.

JohnnyC
New Jersey
Reply With Quote
  #20  
Old 02-09-2018, 12:23:59 AM
consolenut consolenut is offline
Registered-I
 
Join Date: Oct 2017
Location: Bristol, Tennessee / Broken Arrow, Oklahoma
Posts: 305
Thanks: 16
Thanked 75 Times in 59 Posts
Default Re: Onan 12.5JC Sorting it Out

As you can see in the bittommof the carb everythingnisbthere to hang the float etc.
Attached Thumbnails
Click image for larger version

Name:	IMG_20180208_222043.jpg
Views:	40
Size:	72.6 KB
ID:	302702  
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 12:10:06 AM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2016 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277