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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: BIG CHEVY on May 03, 2010, 05:39:42 pm
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ok.............i got a big clear fuel filter right into my carb.
once i crank the engine once everything is fine. starts perfect after that.
problem is....on first start, its VERY hard. the little glass filter will be bone dry and it takes like 30 secs to get gas.
why would gas be returning back down from filter? not normal right? fuel pump? i got a great truck, but its junkpile until first start.
please help. any info appreciated.
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What kinda carb do you have?
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even if gas goes right down the line (gravity) you should still have enough in your bowl of the carb. The gas remaining in the bowl, which comes in through a float and needle valve from the top of the carb body, should be plenty to run the truck at idle for at least 5 minutes before any more gas is needed from the fuel pump.
When the fuel level inside the bowl is high, the float rises up to shut off the needle valve, thus not allowing any more gas in. It works with gravity. Bowl level gets low, float goes down, opening the needle to allow more gas.
I would be interested to see if you your bowl empties for some reason when it sits.
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ill try anything u can think of to diagnose. anything?
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Have you noticed any wet spots around the carb to be almost sounds like the bowl. Is leaking causing lost of suction on the fuel filter and letting it run back down to the tank
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its an edelbrock 1405 maybe? not sure if 1405 is model. says it on front. if its crap, let me know.
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area around carb is kinda dirty so maybe on wet spots. also if u stab the gas hard and quick at any time, it coughs, but wont go dead.
but it will crank fine all but first time.
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Maybe the float is stuck down and not really holding much fuel. Sounds Like when you stomp it down there is not enough fuel to let it go wide open.
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ok.....all options sound good. any fixes? is it bad as buy a new carb? whats the best on market?
mines a 79 k-10 stock 350 stock 350trans, 203tc, but both strong. but remedies also please.
i know im not knowledgeable, but im smart. so dont count me out yet. this is the frist place i had to be mentored. much thanks guys......
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Make sure the choke is working first of all. I really don't think your bowl is leaking, but it is possible. Put paper all under the carb over night or something and see if it gets soaked.
The choke plate should be closed when the engine is cold. If it is even slightly open when engine is cold, it will take forever to start up. The choke plate will open when the engine runs for a minute or two to allow more air in.
When the engine is cold, push accelerator once. See if the choke plate closes. It should.
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Do a fuel volume test. When you experience the problem, pull the hose going to the carb and put it in a glass jar. You should see 1/2 pint of fuel or more within 15 seconds of cranking @ 4-6.5psi
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Yes 1405 is the model. Its a 600 cfm manual choke carb. A rebuild kit is about 35 from summit if it leads to it.
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yeah like beast said its cheaper just to rebuild them if thats the problem
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How about before you start it you look down in the carburetor and rotate the throttle a couple of times. You should see the accelerator pump squirt fuel into the carb. Just thought you may want to verify that you actually don't have gas in the bowl. Is this a daily driver? If it sits for days the fuel will evaporate from the bowl.