fuel overflow/71 454
Fact is the float system only has a few parts and is very simple.....overflowing can only be caused by one of five things:
1) Debris in the needle or damaged needle.
2) Dropped float...saturated nitrophyl or brass float that took on liquid.....
3) Incorrect float level setting
4) Fuel pressure way too high (7psi max on Holley)
5) Damaged/missing needle/seat O-rings seal to float bowl (This is VERY rare and will not "shoot" gas out of the vent, more like a trickle...)
95% of the time it is 1, 2, or 3......if you have a stock pump, 4 is out of the question.....if you see rubber bands on your needle assembly, number 5 is out too.
If the needle is clean and the float actually floats and is set proper....it has to seal. If it is debris or dirt in the needle, then it is coming from somewhere.....like a rubber fuel line inlet failing internally which breaks the inside rubber down to dust that goes right through the pump, through the pathetic screen filters on the bowl and clogs the needle....you clean it, put it back together and it works for a minute until more debris floats through and makes it leak again. So logic tells you......get a clean gas can....disconnect the inlet to the pump and run a long hose from the inlet to the gas can.....clean the needle and try again......
I cannot say enough about float setting either and is one of the mos misunderstood and plain overlooked aspects of any carb. The Holley has a sight plug in it and you remove it while the engine is running.....start with a float setting that is way too low and dial it up until you see a trickle come out......wrap the intake with a damp rag for safety.
Make sure the float floats! Brass is easy....shake it...if it has fuel in it you will feel it....the black Nitrophyl can be put in a bowl of fuel to check......
Check these things and it will work......because it has to.
Jebby
Last edited by Jebbysan; Oct 26, 2021 at 08:19 AM.
Jebby
Last edited by Jebbysan; Oct 26, 2021 at 09:46 AM.






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