BBD will not idle, AT ALL.

Hey guys:

I've spent the last month working on the 1975 Duster Custom I picked up a while back.

One thing was to overhaul the carb. When we drove it home, it tried to die at every stop. It pretty much wouldn't idle, plus it had a distinct whistle.

Well I went through it top to bottom. It did not have clogged idle tubes, or any other clogged passage I could find. I cleaned it thoroughly in solvent and blew everything out with brake cleaner.

I did find that the throttle shaft was loose, and the throttle plates appeared to have been removed and hammered on(don't ask me why).


I salvaged another good baseplate and used that. When I put it back on, it's only running off the main circuit. No idle at all.

I pulled it again and double-checked my work. I discovered that I had used the wrong base to carb body gasket, but even so it did not restrict the idle passages. I corrected that and also switched out the thick idle mixture screws for thin ones.

Long story short is I'm no further along than I was. It doesn't even try to fire and run without pumping the accelerator. It runs ok if I keep it revved but as soon as I try to idle it, it quits dead.

I've seen retarded timing do this, and I'll check that, but is there a hidden passage somewhere in that carb I might not have gotten a blockage out of?

Thanks!

im having same trouble.just got my engine fired up after complete rebuild.broke in cam.runs & revs great,but will not idel under 2000 rpms. iv changed 3 carbs now & same thing.im now in process of removing intake & having it milled.it didnt line up good @ all.had to pri one side down to get bolts started so im thinking i may have an internal vacum leak.purchased block & heads already machined & ready.im thinking heads or block or both have been milled.if this fixes it ill let you know,but if you find somthing that im missing please let me know!kevin

how many turns of the idle mixture screws ?

could be that the blades are open to far.

Try raising the timing to 22* and then see if you can lower the idle/blades and have about 3/4 turns out on the idle screws evenly all 2 or 4 depending on model.

if so, you need to then limit the mechanical advance in the distributor so that you can maintain the high initial but not advance so much as to have it ping and lose power.

what cam?
what compression?

Sounds like the spark plugs are too cold. What plug is in the car?

George

just got my idle prob solved.i moved my positive wire for distributor from ballast to battery+
& it idles!im running an igniter & i must have been losing voltage under 2000 rpm.just need to find another positive source.prob was in ignition all along.