671 blower Carburetors leaking out linkage ?? - Hot Rod Forum : Hotrodders Bulletin Board
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Old 08-27-2018, 06:04 AM
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671 blower Carburetors leaking out linkage ??

okay started my 671 blower sbc i am running two 850 demon carbs
i know little big but that's what i have, fuel pump is holley black

fuel pump regulator is set at 8psi front carb gauge reads 7 psi
rear carb reads 6 psi the problem is both carburetor are leaking
out of linkage back carb started first then the front carb

regulator is a mallory with return 4/12 psi
car was running good before but now started to leak


Last edited by 51CHOPPED; 08-27-2018 at 06:33 AM.
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Old 08-27-2018, 09:10 AM
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you can replace or rebuild the baseplate shafts easy. 850 cfm sounds like a perfect size carb(S).
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Old 08-27-2018, 02:53 PM
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Demon recommends between 5 and 6 PSI fuel pressure at idle. As Vinnie suggested, rebuild the base plates and then drop the fuel pressure to 5 psi. More pressure will not make more power with a carburetor. What it will do is to overpower the needle and seat assembly in the bowl and allow the fuel pump to blow raw fuel into the intake manifold, creating a tuning nightmare that will not be fixed until you lower the fuel pressure.
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Old 08-27-2018, 08:16 PM
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Try lowering the pressure (5psi max) and re-adjusting the floats. I've had high fuel pressure flood my carbs with the excess fuel coming out around the throttle shafts. Lowering the pressure and re-adjusting the floats was the fix.
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