carter afb ?? sugestions

on my daily i have a pretty good 355 sbc and am running a carter 9637 sa afb. well overnight or when parked for a while the carb empties its bowl. i have to crank and pump it for a while before it fires. gas milage is awful for being in a 2700 lb car.10-12 mpg. i lowered the float level a couple times but that does not help! any sugestions thanks mike. cam is a 214@50 442 lift cl is 107

 

most of the times a leak back out of the carb isnt so much a float issue, but a needle & seat leak. the needle & seat is the fuel flow valve that the float controls-- allowing fuel into the bowl (and perhaps out of, in your case.)

-scott noteboom

 

Don't forget that the earlier cars have poor aerodynamics.
I think that's the main reason my 32 roadster doesn't do well on highway MPG.

I'll go along with Notebooms on the needle & seat bit and add that you could be running too much fuel pressure.
Mine runs 4 1/2# -5 1/2# pressure and doesn't have needle/seat issues.

 

To the best of my knowlege, a leaky needle and seat won't empty the bowl, it will overflow it. If it only happens after driving, it could be percolating empty because of engine heat. A thick insulating gasket between the carb and manifold might help.

 

Just install an electric fuelpump near the tank somewhere and bypass the mechanical pump. This will fill the bowls in a split-second.
Once I put a Carter electrical fuelpump on my car the long-starts where over. The fuelpump is a max. 5-6 psi, so no regulator needed. The AFB-needles are 'pushed' open at 8-9psi and higher.