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catgo22
03-10-2011, 07:23 PM
Looking for some ideas. Gassing up off corner, car occaisionally acts like it's flooding. Cuts up for a second, then goes. It's a 400 with rear mounted KSE, 6 PSI fuel pressure, a 950 Marx Holley, a flat (not tilted 2 inch spacer). It does not seem electrical. Seems fuel related, like fuel surging into the barrels. I lowered the floats a little and that seemed to help but it's still there. But worried how low is too low. Thanks.

joedoozer
03-10-2011, 07:34 PM
Well you could go the other way with the floats. If you suspect its because they are too high, then make them a little higher. See if the problem is still there. It's safer than running it too lean. Does the car have a Bert style trans or a conventional like an old 4 speed? Could you shut the motor off at the end of the straightaway to get a good plug reading? I have seen a bad power valve leaking and guys would lean the idle screws almost all the way to try and keep it idling. Just an idea.

Kwaz-13
03-10-2011, 08:29 PM
Don't write off the electrical unless you've replaced the toggle switch. Not guaranteeing that is the problem, but I've seen a lot of $$ spent that would've been saved replacing that 10-dollar part.

big88fan
03-10-2011, 08:50 PM
I had the exact same problem last year with a new out of the box willys carb I had fuel splashing out of the front vent I lowered the float for that night cleared it right up but bought the new style vent tube that goes between both vents from KB

ptodd
03-10-2011, 09:45 PM
i would like to see 7.5 lbs pressure. if your car is rolling up a bunch and carring the wheel i would put a tilted spacer on it

jim4x
03-10-2011, 10:24 PM
Try a piece of fuel hose connecting both vent tubes with a notch cut out of top of hose,easy way to check fuel slosh

catgo22
03-11-2011, 12:35 PM
Thanks guys... Did check the ignition switch and electrical connections. The car does jack itself up pretty good and the bridge vent tube is a great idea. Will try it.

ptodd
03-11-2011, 03:37 PM
If the vent tube fixes it put a angled spacer on it

catgo22
03-12-2011, 01:23 PM
LT, it's only 403 but SB2. Made 790 and jetted to where the plugs look good. Spoke to KB. They suggested that the fuel pressure may be too high at WOT. Overloads the needles at end of straight, then blubbers... Said to get it down to 3-5 at idle and 7 at high rpm. Will try that. I got a feeling this is the problem.

nineteen
03-19-2011, 04:49 PM
Not telling you this is the solution but I drive a Rocket that gets rocks up pretty good and i was having the same problem. I talked with my carb guy and we came to the conclusion that the fuel was blowing past the neddle and seats, I put a fuel pressure regulator on just before the carb and set the pressure at 7 lbs. at idle and set the floats normally. It seemed to fix the problem and the car came off the corner smoother and was more consistent all the way around.

j20000
03-25-2011, 08:18 AM
Mechanical Fuel Pump? Or belt driven off the back of the motor?

rubbinsracin
03-30-2011, 12:31 PM
how much timing are you running? we have similar issues w/ our 383 and have though about bumping up the timing a degree or so to help take care of this.