Vapor curling from a 1450QF

[ojh]

A buddy has issues with his 1450 QuickFuel, he has vapor curling from the venturii after shutting engine off, the fuel level is in the lower 1/3 of the sightglass and he says boosters are not damp but dampness on throttle blades. Is this coming from the Intermediate Ckt? Is it getting some kind of vacuum signal to let a dribble or two out after engine shut off?
Thanks, Oj

[jmarkaudio]

Drag car I presume? What temps is the engine getting to?

[ojh]

Yes, drag race. He says the motor isn't all that warm to see the vapor, 150deg or less. Mostly when he fires it up briefly and the motor is cold to begin with, he does see it after warmup to about 150 degrees to get everything to temperature. It is just with this one carb, he has other, smaller, carbs as well - prosystems - that don't do the vapor. They are smaller, maybe 1350?
He said he just spoke with QF and they say its normal, they confirmed he had fuel level & pressure correct.
This just occured to me, he has at least .130 N&S, maybe .150, and huge MagnaFuel front mounted pump & cell that has 26? 28? psi and I believe they have an internal checkvalve to keep the line pressured. Maybe he's getting seepage past the N&S to overfill the fuel level causing dribbles?

[RFSPHPbb]

it's fuel evaporating out of the intake. not really an issue. ignore it.

[ojh]

Any thoughts Mark?

[jmarkaudio]

I wouldn't worry. But I would look to lower the pump pressure, try to get it under 20. And try creeping up on the intermediate bleed, jet up as needed to compensate.

[bigblockmark]

Mark. Sometimes i see recommendations to just pull the intermediate air bleed on a 3 circuit dominator. Is this a safe practice? What does it do to the fuel in that circuit? Does it take much more main jet if doing this?

[jmarkaudio]

It's not always as simple as pulling the intermediate bleed. If I have a rough idea on HP and carb size I can usually gauge what is safe. Some of the bigger carb calibrations can be marginal getting enough fuel if you lean it too much or plug the circuit, sneaking up and adding jet to compensate is the best way with the original metering blocks and calibration. .010 at a time on the bleed is fine to start.