i just rebuilt the carb now it runs worse

[73Scamp]

ok it's a stock 225 slant six with a holley 1920 1 bbl i just rebuilt it now when i'm driving in the city it's fine but at 65+mph it's running rough and it has bad run on and smokes while it's running on the smoke comes out of the air filter i'm thinking it the timing but why is it worse now that i've rebuilt the carb i'm thinking on my next day off i'm gonna replace the plugs and rotor and cap i plbably should do the wires as well but i can't afford that right now not with getting married in 5 weeks :shock: i can't believe i only got 5 more weeks! but anyways got any ideas about my problem

thanks
rob

 

[OUTLAW]

if I get this right its ok @city speed but rough and stumbles at higher speed. Does this car have a catalytic convertor in it? check for plugged . if poor running started after carb rebuild dbl check the float level and baseplate gasket . Obviously it must of been giving you trouble befoore you rebuilt the carb so definately pull the plugs and clean them- probably loaded up from prior poor running . What was the original problems b4 you built the carb?

 

[superdart]

Best way to reuild a carb is to replace it!!!

:bounce:

 

[73Scamp]

i rebuilt it because of occasional run on and it started leaking gas into the intake after i shut the engine off so it was really hard to restart when warm i put a new base gasket on iand i tightened it good.

secondly i know i should just get a new one but that would mean getting a new intake and a bunch of other things cause i won't replace it with a stock 1 bbl

 

[OUTLAW]

very possibly a heavy float which would account for the overhaul carb not fixing anything if you didnt replace it--also would account for your previous problem too

 

[sweatybetty]

a plugged fuel filter will cause poor higher speed driving. not enough fuel.maybe you got something in a passage somewhere.i wouldnt mess with the timing yet.

 

[Guitar Jones]

Those year slant sixes were known for having heat soak problems as well as bad floats. You probably have a combination of problems. You did check and set the timing right? All the emission equipment still intact and functioning? If not, you just found part of your problem. EGR is very important to an emission calibrated engine as it keeps combustion chamber temperature down. This could be causing your dieseling problem when you shut it off. Along with crappy fuel or too low of octane. There's a lot of things that will contribute to your problems so you'll need to take them one by one.

I would first replace the floats with new ones and set them so the top of the float is even with the top edge of the carb bowl. Next you need to make sure the power valve is free and not sticking. Then I would probably drill the jet to the next drill size from what it is, be really careful here but these carbs were set up so lean they were beyond borderline. Reset you timing and drive the car. If it spark knocks retard the timing a few degrees at a time until it stops. Don't go past 0. You may be able to go as high as 16 though, all depending. Then turn the idle speed down as low as it will go and turn the mixture screw out a little to fatten it up. This should stop the dieseling. Good luck.