Hey guys looking for a little help here! all my plugs have black soot on them, i understand that it shows an over rich mix but my holly one barrel 1920 has one screw and i have adjusted it, no help, it will run for a while until the plugs go black again, i clean them, try to adjust the carb again and in no time, soot again! it`s driving me nuts,! heard it could be a dirty air filter, but im running with no filter when testing, could be the choke, were should the manual choke be, wide open or slightly closed "what?.. these were brand new plugs and it really sucks! which way is lean on that mixer screw? --has anyone heard of this condition, i cant even drive it this way, it happens so fast that i have no time to even go around the block ! please any help appreciated 71 dodge dart/225/slant six/holly one barrel 1920/3.7L E[/img]

Dartboy71,

That is a pretty simple carb and it can work very well. That is what I am using on my car.

The choke has to be wide open once it is warm. If not, it could soot those new plugs up pretty quick.

Is the car stock? If so that is an automatic choke. If the choke pull-off is working it should pull the choke back once warmed up. If not, it could mis-adjusted, have a ruptured diaphragm or the vacuum hose going to it could be leaking.

Send me your email and I will send you a tune up guide for the carb or you can do a search on this site for it too.

When you turn the mixture screw in, that leans it out.

Let us know....

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

but if he's into the mains the mix screw (which is only for the idle circuit), then his jet is too big... and another problem... 'if' his lash isn't adjusted or the car isn't in a good state of tune, then he may have 'poor' vaccuum at idle, low enough to cause the 'economizer valve'/ aka the power valve to bounce open and make things over rich...

Priority would be:

Check choke, when engine is warm the plate should be open (90 degree angle to the carb top)
Next make sure the linkage and vacc. pods are all in good order.
Next check and make sure your valves are properly lashed per the manual...make sure all ignition components are in good shape and the timing is set correctly.

If all that's good and you are still sooting up the plugs, you'll need a carb rebuild and you'll want to see what main jet is in there (if it's a remanf, they just put in whatever they feel like- I just broke down a remanf Holley 1945 which should have no bigger than a #612 jet in it... it had a #65 in there... wayyyy too rich... the Holley 1920 should be good with a #57-58 tops depending on driving/climate/altitude conditions...

good luck,

-D.Idiot

Thanks guys, i checked most of what you said except the valve lash, ill check that next, where on the site can i find that tune up guide? oh, by the way it`s a manual choke. 71` Dodge dart/225/slant six/3.7L "E"/holly one barrel 1920/