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Carb flooding

M

mxnocean

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Grover Beach
Hey guys, im not good with carbs so please bare with me. 1968 suberban, stock 454 in it. Been sitting for a loooong time (7 plus years) I got it running, drove it for about 20 miles around town etc. Decided to the carb off and clean it by just using carb cleaner and spraying it. Put it back on and runs super flooded. Tried messing with it and nothing. It was an old carb so I just decided to buy a new quick fuel 670 carb. Put it on made sure everything was legit on it. Floats, air/fuel mixture screws etc. And now it runs even more flooded!!! Can even drive it now. Any ideas what it could be??
 
About the only thing it could be is a fuel pressure problem. Especially since it has the same problem with two different carburetors and one of them being brand new. Get you an inline pressure gauge.
 
GM Q-Jets used foam floats that ethanol can swell up,make them sink, or dissolve,if your had the old floats in them this may be why they began flooding..

On a old big block with a factory mechanical fuel pump there isn't much you can do to "adjust" the fuel pressure--usually they are calibrated to only produce the needed 5-7 lbs of pressure and enough volume to supply the carb under all conditions..
If the diaphram in the fuel pump is old and stiff,the pressure may increase --usually one in that condition fails soon after and begins leaking fuel into the crankcase and on the ground thru the weep hole in the casting..

There are high pressure mechanical fuel pumps available aftermarket--but you don't need one.
 
I put a furl pressure regulator on it at set at at 6psi. Still running bad. Like it has a .488 cam in it lol. Think it can be a spark issue?
 
Pull plug take pictures, Choke? Are you pumping the gas pedal too much
 
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Is choke opening all the way?
Can you see excess fuel running into the primary bores?
 
Are is he looking in the carb to see the fuel? I have seen a lot of "flooded carbs" be firing issues. He said he doesn't know much about carbs and 2 doing the same thing is odd.

Was anything else done when the original carb was removed and cleaned?
 
Thankyou for the replies guys. Nothing was changed when I put the new carb on. I triple checked all the settings on the carb. Bowls, mixture screws on the metering blocks, etc. and like I said I put a fuel pressure regulator on it. I did check the plugs and they were black as hell. Changed those and still had the same problem. Sounds like a a flooded clapped out motor. Oil is good, valves are good, the only thing I haven't checked is cap and rotor. When I did put the fuel pressure regulator on it and turned it downed to 3psi it would starve for fuel and die, but when it would die it still sounded like a clapped out cam in in it, thats what drives me to a firing issue??
 
What did you do to check the floats on the new carb?
Is that carb a double pumper. Meaning does it have an accelerator pump on the bottom of each bowl?

Adjusting the front bowl idle mixture screws...you should be able to turn them all the way in (dont overtighten) and the engine should stall out. If its a double pumper you will have to turn the same screws on the rear bowl as well. Start by turning them out 1-1/2 turns on each, when you get the floats right, adjust these screws 1/2 turn each in equal increments until the best idle quality is achieved...highest rpm, and smoothest idle. Adjust idle speed as necessary.
Check the timing as well.

try adjusting the floats per this procedure:

 
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I did specifically what quick fuel recommended for a stock 454. On the sight glass the fuel level was maybe an 1/8 inch visible on the sight glass on front and back bowls. And I have adjusted them to different settings (raise and lower) the bowls to see if that was the issue, still runs the same
 
If you dont have fuel in the sightglass, I dont know how it could be flooding? How far out are the idle mixture screws?
That carb should have powervalve blowout protection, but if the power valve(s) are nad that would cause it to be heavy rich.
 
It has never back fired through the carb which I think the power valve would blow out. The mixture screws are 1 and half turns out (stock) this is why im leaning towards firing issue.
 
If its been sitting that long wouldnt hurt to pull the cap and have a look
 
I'm definitely going to do that, especially going through all the fuel delivery shit. Basically brand new everything, and the only things I haven't done was go through the ignition (firing spark plug wires, cap, rotor, etc)
 
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