" I get raw fuel out of the exhaust and black smoke"

[Grumpy]

I rebuilt my 6210 holley spreadbore but I cannot get the car engine to start long enough to adjust anything. I turned the idle mixture screws out 1.5 turns. The engine will start for a couple seconds then dies and won't restart. but smells very gassie. I get raw fuel out of the exhaust and black smoke. I get fuel from the accelerator pumps.

Most 4 barrel holley carbs have an adjustable fuel bowl float level and are designed to work with 5-6 psi of fuel pressure at the carbs inlet port, over 6.6 psi will frequently cause the needle valve to fail to seal and flood the carb/engine so you should verify your fuel pressure at the inlet port.
the needle valve is controlled by the float level and in most holley 4 barrel carbs, this is generally externally adjustable, provided the carb was properly assembled with the floats internal lever or tab resting on the needle valve in the proper location., and providing the floats not bent or damaged and the needle valve seats not dirty, broken or improperly installed

some times fuel bowl floats can become hung up in the fuel bowl, a couple good hard whacks on both fuel bowls with the plastic handle of your screw driver will frequently allow the floats to drop to the intended level, if not disassemble and visually check that out and don,t damage the gaskets.
it sounds like the float levels need to be verified, your carb should have removable float bowl plugs or sight windows , the float level should be set at idle near 700rpm-800rpm, Id strongly suggest you back out the fuel bowl sight plugs and adjust the needle valve controlling fuel level until only the bottom threads in the fuel bowl sight plug hole get DAMP with fuel but fuel does NOT leak out.
if the needle valves are open there will be raw fuel trickling into the carbs throttle bores as it floods
youll need a 5/8" open end wrench and a 3/8" wide flat blade screw driver

http://forums.holley.com/entry.php?...Adjustments-On-Holley-Four-Barrel-Carburetors

http://www.racingjunk.com/news/2014...nd-floats-on-a-holley-four-barrel-carburetor/

ID suggest having a large soaking wet, with water, bath towel, handy as a precaution should you find the carb catches fire from an ignition back-fire , throwing a large soaking wet towel over the carb if it should catch fire tends to put it out and limit potential damage to the cars engine compartment!, obviously having a CO2 fire extinguisher handy would be great! NEVER WORK ON THE FUEL SYSTEM INSIDE OR NEXT TO A BUILDING AND HAVING AT A MINIMUM A GARDEN HOSE WITH A SPRAY NOZZLE AND THE WATER TURNED ON BEFORE YOU START WORK MAKES A GREAT DEAL OF SENSE, SIMPLY BECAUSE common sense says, having a car on fire inside your garage risks much more than the car! moving the car outside away from your home, as a precaution, limits potential damage

whats the inlet port fuel pressure read?
if youve checked the carbs inlet port fuel pressure, and if its much over 6 psi chances are very good the fuel pressures forcing the needle valve off its seat, and youll need a return style fuel pressure regulator to get it to function correctly

http://garage.grumpysperformance.com/index.php?threads/fuel-pressure-regulators.635/


http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

READ THE LINKS

http://garage.grumpysperformance.co...u-need-to-know-setting-float-levels-etc.1115/

http://garage.grumpysperformance.co...-fire-extinguisher-handy.81/page-2#post-42551

 

[Grumpy]

Thanks Grumpyvette. It was suggested that I fill the float bowl through the vent, to give my starter a break. I tried this, while filling the float bowl I could hear gas trickling. I removed the carb put it on a plastic pail refilled te float and the fuel ran right out through the baseplate near the middle front screw! I disassembled the carb for the 3rd time but could not find any gaskets out of place. Still same problem. Drained 6 quarts of oily gas from the pan and changed the filter. I had a 780cfm carb on the shelf for years pulled cleaned it up installed it filled the float and it started and runs great. I guess I'll just tune the 780 and go from there.

I.m always grad to help where I can, and ,I'll point out here!
like most good mechanics you've learned to think a bit and logically diagnose the issue based on what you see and test , isolate and test is the key..guessing and random parts swapping rarely works to anyone's financial advantage