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dave284

I have 78 gmc vandura with a 350, i been going crazy trying to figure out what I might have missed on a tune up. It started one day the van was smoking and running slugish so i changed the plugs, wires and cap....still didnt help, and i notice a strong gas smell too...so i rebuilt the carburetor, still no go, got a new one still flooding so i thought it could be something in the ignition system, replaced coil and ignition module .....well still flooding and it has a good spark, timing set at TDC on #1 , battery fully charged, and compression is between 130 to 140 PSI. I also done a valve job on it new valve seals and headgaskets too,also drain the fuel tank and installed new fuel pump the only thing i havent checked into is the timing chain...could a worn timing chain cause flooding? Im at a lost on this van:confused:

Oldcar_Mechanic

If it is truly flooding (you could verify by looking down the throat of the carb while at idle and see fuel dripping) then your problem is most likely a carb problem. Leaky needle and seat, heavy or sunk float, a float (if brass) filling with fuel making it heavy. This is of course if the throttle is really at the closed position. Sometimes I have seen the throttle open some to keep it running due to other problems like a vacumm leak. The throttle plate should be fully closed at idle. I have seen rebuilt carbs that are bad and have replaced 2 or 3 before getting a good one.

Another possibility could be a high fuel pressure.

Other mechanical issues like the timing chain will not cause a carb to flood. It can cause bad timing and the car to run like crap though.

Ron

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