Piston Slap: A Chevy’s floaty Will Carter?


Sidney writes:

I rebuilt a Carter WCFB 4 barrel carb on my 1955 Chevy. Fuel pump working as it should (pulsates and sprays gas each time cam lobe activates it). Though the fuel float bowl is full, can’t get gas into the accelerator pump chamber of the carb. Can fill the accelerator chamber with a syringe (through top open passages of the forward barrels where choke butterfly is) and the jets will spray gas into the forward chambers (and will idle and accelerate for about 15 seconds) but when that gas is depleted, the spraying stops. I have repeated multiple times with the same results. Can you help me out? One caveat…it’s my “impression” that the float bowl is full because when I disconnect the fuel supply line from the fuel pump (to carb), it has pressure on the line.

In my repeated attempts to get the accelerator valve to pump, the car has run for several minutes combined, plenty of time to get the float bowl full. Could the float bowl actually be the problem? Even though there’s pressure when the fuel supply hose to the carb is disconnected, could it still be the fuel pump (I installed a new fuel pump)? Thank you Piston Slap!!! (By the way, I like the site name)

Sajeev answers:

We recently discussed the Will Carter Four Barrel on a DeSoto, which had a different problem with a similar solution. I am very, very confident there’s a sticking issue with the float(s). But first, check the fuel pressure at the fuel line: I suspect it’s within spec (usually between 5-10 PSI) but maybe it’s just low enough to keep the floats from doing their job. Again, while highly unlikely, it’s usually a good idea to check the actual pressure reading before tearing into the carburetor.

WCFB carburetor diagram illustration
Danger Will Carter? Mike's Carburetor Parts

Like we said in the previous Piston Slap about the DeSoto, check out the WCFB repair manual from Mike’s Carburetor Parts. The heart of the issue is likely found on pages 77-79, but his YouTube video is rather priceless and worth sharing again:

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