Carter BBD Vacuum Piston Adjustment Question -
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Unread 02-23-2013, 02:20 PM   #1
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1983 CJ5 
Join Date: May 2011
Location: Huntsville, AL
Posts: 5
Carter BBD Vacuum Piston Adjustment Question

When I first rebuilt my Carter BBD a little over a year ago, the initial results were great. Over 15 MPG in my '83 258 CJ-5 with a 4 speed manual. However, I was never able to get the idle speed correct, so I set about readjusting from the beginning. When I hit the vacuum piston adjustment, I found a discrepancy between the CJ repair manual, and the rebuild kit instructions. Below are pictures from both:



So, which is correct? Initially, I followed the method shown in the CJ manual, but as I think about the function of the vacuum piston, the rebuild kit gap location makes more sense. Any input would be greatly appreciated.

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Unread 02-23-2013, 02:51 PM   #2
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86cj74.2L's Avatar
2004 WJ 
Join Date: Jul 2006
Location: Stouchsburg, PA
Posts: 8,821
I used the one in the picture from the rebuild kit.

Are you accidentally looking at the piston assembly of the older carb?

Don't forget to back the idle screw off all the way and loosen the screw that operates the piston assembly and push all the way down to compress the spring them tighten the screw.
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