Carb troubles?

[RECHRGD]

On my way to a car show this morning, I come to a stop at a light and the car dies.  It restarts but won't idle.  Got in into a parking lot and started looking under the hood.  Found the main connection from the coil was corroded and burnt on the inside.  I had a spare coil, so I put in on.  The car started up and seemed fine for about 10 seconds and then the idle gets rough and drops down in rpm to the point of stalling.  I was able to baby the car back to my storage unit by keeping the rpm's up at the stop lights.  The fuel filter seems fine (I could blow thru it fairly easily).  I adjusted the main idle screw so that the engine would idle at about 1200 rpm.  Again, after start up it seemed fine for about ten seconds and then the idle dropped and got rough.  I loosened the site screw on the rear bowl with the engine off and there was fuel there.  Fuel pressure at normal idle is pretty steady at 6+ pounds.  When the idle drops and get rough the pressure bounces between 3.5 to 5 pounds.  The carb is a Holley 750 DP w/ a Proform main body.  Engine is a mildly built 440 with a 727 tranny.  Help, Bob........

[XH29N0G]

I'm not an expert and you may have other reasons for looking to the carb, but it seems that if the car was OK before the coil went that it should be something spark rather than fuel related. 

[RECHRGD]

The coil didn't fail.  I just replaced it because the connection was marginal and hoped that was the problem.  It wasn't......

[Back N Black]

Have you checked the fuel pump push lately?

[Brightyellow69rtse]

i was thinking the push rod aswell.

[c00nhunterjoe]

He said he has 6+ pounds of fuel pressure at idle. Doubt the pushrod is bad.

[resq302]

almost sounds like you developed a vacuum leak which is causing the engine to die out.

[Chryco Psycho]

could be a vacuum leak or bad gasket in the carb or just dirt in one of the air bleeds

[Cooter]

Sounds as if could be a little sh*t got up into the carb. Ever see what this sh*t they call fuel we are paying three prices for looks like after sitting [As you mentioned Storage facility]?

Yep, looks like Black molases...I'd try revving the engine and doing what I call the "Redneck rebuild" on the idle circuits. Try revving the car, holding hand over primaries until almost stalled about 5 times and see if things are better. If so, then time to pull a float bowl and have a look see.

[c00nhunterjoe]

Look down in the carb and see if fuel is dribbling while its idling. Could have a float stuck or som dirt on a needle\seat.

[RECHRGD]

The gas is pretty fresh.  I went back and checked the pcv valve and looked for any obvious bad vacuum lines and all looked ok.  I pulled the carb and brought it home to check out.  When pulling off the carb I noticed gas puddled on the top of the gasket but I couldn't see signs of a leak.  The gasket is one of those thick ones designed to be a heat sink and just installed this spring.  I pulled the bowls off and the floats are fine except for a little corrosion and the power valve is good.  I'll go and check the needle valves in a bit after I wake up........

[RECHRGD]

OK, the needle valves looked good but I sprayed them with carb cleaner and blew them dry.  Found two air bleeds and one secondary jet with some restrictions.  Cleaned everything up and put it back together.  I didn't trust that the thick heat sink gasket was sealing good, so I added a thin one on top of it.  Just took it on a 50 mile drive with no issues, so something fixed it.  Only problem is that I can't get the idle back down where it was before.  I think the throttle cable is binding a little because of the added gasket.  It's idling at about 950 in gear, but I can deal with that later.  Thanks for all the suggestions.   Bob

[Dmichels]

Check for a bad float and or seat Extra fuel dribling out out idle will stall any engine Happened to me
Dave