304 Holley Carb Tuning - JeepForum.com
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post #1 of 2 Old 09-08-2009, 07:30 PM Thread Starter
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1991 YJ Wrangler 
Join Date: May 2009
Location: Medford
Posts: 23
304 Holley Carb Tuning

I have been fooling with my carb for awhile and have not really gained much so I figure I would post some specs and see if anyone has any suggestions.

This is a mild built 304 with a mild cam (not sure any spec's info from PO) Eldabrock intake, factory exhaust manifolds and custom 2" dual exhaust.

I have a Holley 600CFM 1850-3 Carb which now has 64 Main Jets, #65 PV and a black vac secondary spring. Checked vacuum at 13". I have set the bowls so a trickle comes out of the sight plug when rocked. I have not touched the secondary as it is my understanding on this carb it is a plate?

My problem is I am running rich at idle and at speed. I can smell gas all the time. Checked plugs and thy are a little black around the outside and dark brown in the center. I went down from 66's to 64's on the mains based on what the Holley instructions recommend.

Any suggestions would be greatly appreciated

1991 YJ 4.0,Auto, 2" Rocky Road BB, 31X10.50 Hercules Trail Diggers on Factory 15X7 Steel
camjeeper is offline  
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post #2 of 2 Old 09-08-2009, 08:56 PM
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1978 CJ5 
Join Date: Aug 2009
Location: Loveland
Posts: 338
Just been getting a holley 470 truck avenger dialed in on the CJ I just bought for my son. Also edelbrock manifold as well. Start with your idle mixtures adjust screws on each side of your primaries. Turn each in a 1/4 turn and run it see how you feel/smell. Mine was at least a full turn to far out, made my eyes water. I also have ordered smaller mains. I was .057 moving down to .056, not much but lets see. I am at 5500ft so I for sure will run smaller than your .064s. Also if you have a vacuum gage some of the more skilled will chime in and tell you to use it and I think go for max vacuum when adjusting the idle mixture screws. Still others may tell you turn them in until it starts to falter then back out 1/4. If you can't get it with mains and the idle mixture screws then time to play with your power valve. The smarter guys will have to take it from here.

78 304-CJ5
texasimport is offline  

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