54 olds. 324 with 371 Pistons and heads. 1955 4bbl intake. Rebuilt complete engine and carb. Still working out kinks. Throttle shaft is slightly worn so carb has been running a bit lean but I finally got it dialed in best I could. Accelerator pump adjusted and got rid of my hesitation off of idle. Other than that it has been running pretty good. All of a sudden if I let the thing sit for more than a day, as soon as I start it up gas starts pouring out of all shafts and everywhere else you could think of all over intake manifold. Stuck floats right. Pulled of airhorn. Floats seemed to move fine. Adjustment is fine. Put it back together twice. Works fine for the rest of the day. Sits more than a day. Same thing! Even tried shaking car around before start up but doesn't seem to change anything. Could the check valve(ball bearing) at bottom of accelerator pump bowl cause any of this too? Each time I've pulled it apart I've used a pick to make sure the ball moves and it seems to be stuck each time.
Have you checked fuel pressure yet? Mechanical or electric fuel pump? Fuel tank vented properly? Did you adjust the bowl vent when you did the rebuild? Looks like the needle and seat mount into the airhorn on this carb. In addition to the float level did you also set the float drop?
Last winter, when I went to Florida, I took a couple of 4-BBL carbs to rebuild, a 4GC off of a '53 Olds and a Carter WCFB from a '54 Chrysler. The Rochester was no problem, but the WCFB had sloppy throttle shafts. You really don't want to invest a lot of time and a kit (which are pretty expensive), on a carb with slop in the throttle shafts. I found a vendor on eBay that sells a kit of 8 throttle shaft bushings and the proper reamer for around $40. It worked really well for me. If I were you, I would dissasemble the carb, install the bushings and double check everything else. Carburetors are precision devices, and need precise work. If you need the eBay source, get back to me; I'm sure I can find it.
Do you recall if the needle is a black rubber tip, or is it all steel? I just had a 34 Cad/LaS here that acted like yours, and it was a black rubber tip needle. I replaced it with all steel needle and no more problems so far. I am guessing the rubber swells up from gasahol and deforms out of round shape, so it leaks?? Might not be what your problem is No it won't cause flooding over
is the "float drop" set correctly? also check that the floats are not hitting the sides of the bowl when the fuel level is low.
Yes float drop set correctly. Mechanical rebuilt fuel pump. Keep in mind that when I pull the thing apart and move stuff around and reassemble, it will work fine all day long until it sits for a bit. And yes it has the rubber tipped needles. I am going to pull it apart again and check those out. Could be that when I work them back and forth they start seating and then distort after sitting.
Ok. Took everything apart again. Found a very small amount of fuel in both floats. Hardly even enough to notice. Can not even see pin holes with naked eye. I guess it was just enough to maintain buoyancy if it was moving around but left stagnant would hold needles off just enough. Replaced both floats-see what happens
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