I have an edelbrock 600 carb. If i crank the motor too long and it doesn't start, fuel pressure builds up in the bowls and it squirts fuel long after i quit cranking. What is wrong?

 

What does your fuel system consist of? Where is fuel squirting from?

 

mechanical fuel pump, filter, edelbrock 600 carb

 

Is it a stock fuel pump? Where do you see fuel squirting from?

 

it's coming out on top of the carb, everywhere. Why is my carb building this kind of pressure?

 

sounds like hight float level and or leaking needle and seat maybe

 

The carb doesn't build fuel pressure. The fuel pump gets fuel to the carb via pressure, but the fuel in the carb should be at atmospheric pressure. If it's coming out of the carb, it's because it is overflowing, which 9 times out of 10 is a problem with the needle/seat float valve continuing to allow fuel into the carb when it should be shutting off the fuel flow. As stated, dirt in the needle/seat is a common culprit.

 

The above is all true, but you may want to have a look at the fuel pump
pressure.

If the pressure at the needle/seat valve is more than about 9 PSI, the float
can be forced down and cause the needle to lift away from the seat.

Check that the fuel return line (if equipped) is not pinched.

 

BTW- Edlebrock's are notorious for not tolerating high fuel pressures. Most people say 5 PSI is about it before problems start. At 7 you're apparently just ASKING for trouble with them.

I don't use them much so I won't say I've got personal experience with it, but I've seen many people post problems similar to this over the years and my general take on things is they are more "touchy" about fuel pressure than other carbs- even QJets, which also can't take high fuel pressures.

 

That's nuts. Most mechanical pumps are on the thin edge of providing that
pressure at idle. It's no wonder that most engine's I've tuned with Edelbrocks
have had rich idles.

 

I have used a bunch of the Eddys and I have had problem with too much fuel pressure on most performance aftermarket pumps but very few problems with stock pumps. Your fuel control valves(needles and seats) are not controling the fuel flow. If they are clean and tight, you might try lowering the floats a little. If you take the top off the carb and invert it you can use a hand vacuum pump to put a vacuum on the inlet fitting. If it holds vacuum, the valves are working, if not you must fix the problem.