Almost stalls under hard corners and stops

[rsimoes]

My engine is a big cube FE with a Quick Fuel Q850 carb and when I pull a u turn quickly, a long turn quickly or a quick stop and clutch it, it wants to stall.

Normally the idle is around 1100rpm when I first stop and it settles to 900rpm after a couple minutes.

But when I turn or stop as indicated above, it drops to 300rpm and then I tap the gas and it normalizes.

The float bowls have a sight glass and the gas is halfway up on the sight glass. Should I lower it a bit or what else could cause this?

[Jim Werth]

Sounds like its splashing out the vent tubes.

[RedBarchetta]

Originally Posted by rsimoes

The float bowls have a sight glass and the gas is halfway up on the sight glass. Should I lower it a bit or what else could cause this?

Fuel level is too high. The proper/standard adjustment is that fuel should barely trickle out of the sight plugs when they are removed.

[rsimoes]

I'll lower it and see what happens. I thought that might be the issue. . . Thanks! How do I lower it?

[xlr8or]

From the Holley guide at: http://holley.com/data/Products/Technical/199R10321.pdf

1. If you do need to adjust this, loosen the lock screw and turn the adjusting nut clockwise to lower the fuel level and
counter-clockwise to raise the fuel level.
2. Tighten the lock screw while holding the adjustment nut. Make sure the fuel level is mid-level to slightly below center of the
sight glass.

[mr0077]

Rsimoes, you I'm not familiar with the carb you have, but I'm with RedBarchetta on the adjustment...try this link.
http://www.holley.com/data/TechServi...Carburetor.pdf
I had a similar problem on two Holleys and lowering the fuel level fixed her right up...

[scootter]

When you lower the fuel level it will lean out the engine. I have the Barry Grant carb with the fuel level in the lowest position. Even at that position, I will get a slight stumble in a hard off camber corner or hard braking. I had the same problem with my Holley HP 1000cfm carb. I tried three or four different kinds of floats. Still had the same problem.
Scott

[RedBarchetta]

Another fix is adding an extension for the vent (which is in the upper portion of the float bowl), or adding "slosh tubes" which are more commonly referred to as "jet extensions". When you brake hard, all the fuel in the primary float bowl surges to the front of the car, thus exposing the jets to air and causing the lean stumble that you are experiencing. Same with hard cornering (the U-turn), where you potentially expose one of the fuel jets to air. The extensions will cure that problem, but I'm also running a BG and am not sure if they offer the correct "notched" floats to clear the extensions. You have to change the floats to run the extension, otherwise you have clearance issues and the floats will hang up high. My car still stumbles under hard braking, but I just haven't been motivated enough to do something about it.

-Dean

[bnewell]

Same thing happened to me Rob.......my mechanic adjusted the carb and it has been fine since.

Take care,