I have a 73 duster ,and just rebuilt the 1 barrell holley on the 225 slant 6. It idles and pulls decent, but i have the ideling screw turned just about all the way in .If i back it off it wont run.If anyone can please help.

hillbillygirl@triad.rr.com

Fuel is "leaking" into the idle circuit. This can be caused by a loose "swedge plug", loose or leaking valve body / gasket or a mis calibrated "economiser valve".
DD

Doc - could you elaborate a little on this please - or someone else maybe?
Thanks,
Dan

gramma@dm-tech.net

Take the float bowl off a Holley and you will see it's "valve body" (really a fuel metering block)and this is where all the fuel is regulated to suppoet the different fuel "circuits". (idle , cruze and power)

These blocks have a bunch of small passageways, check-balls, air bleeds and plugs so any clog, loose part(s), a crack or warp, corrosion or leaking gasket can cause trouble.
1920 metering blocks are fussy things and hard to service, best to "swap-in" a different one then waste a bunch of time troubleshooting / repairing one that is not working correctly.
DD