float bowl level

[Voyager]

Took my new Cobra for a spin today. Need to address a couple things. The car is occasionally stalling when I come to a stop. Idle is set at 950 rpm. Engine is a Keith Craft 408 street crate motor. Carb is a Quick Fuel Hotrod Series Carburetor, HR 750. Noticed the fuel level in the float bowl windows are both at the top. Should they be at ½?

Bob

[FWB]

they should be at the bottom. i assume you have the clear sight windows. normally there are screws in the holes correct float level should be when fuel barely drips out of the hole when running.
so with the clear sight windows you should not see an actual fuel level. if you do the level is too high.

[ratsnst1]

Originally Posted by FWB

they should be at the bottom. i assume you have the clear sight windows. normally there are screws in the holes correct float level should be when fuel barely drips out of the hole when running.
so with the clear sight windows you should not see an actual fuel level. if you do the level is too high.

my barry grant carb did the same thing, I called the tech dept at barry grant, they told me to have front bowl at a quarter, of the sight glass and the rear bowl at the bottom of the sight glass, and guess what no more stalling.

[Keithc8]

Both suggestions should help. Make sure that your fuel pressure is not more than about 7 lbs. To much fuel pressure can cause the needle and seat to leak. Set the float levels like mentioned above and it should help. I feel that when you come to a stop you are getting a little pushed out the air vent possibly in the back and flooding you out. Do you notice a little black smoke when you restart the car?
Good luck, Keith

[Voyager]

I’ll lower the fuel levels. Stupid question time - to lower the fuel level in the bowl, do I lower or raise the float? I experimented with raising and lowering the float in the rear bowl and could not see the fuel level consistently move up or down in the sight glass.

Yes - black smoke when I restart the car.

I’ll verify the fuel pressure with the engine installer.

I’m loving the motor…

[Calbullet]

Voyager, to lower the fuel level, you need to lower the float. also you will need to rev the engine a couple of times to use the excess fuel in the secondaries. this will let the rear bowls find there levels.

[FWB]

um, i think you have that backwards....if the float goes lower it opens the needle.

anyway turn the nut clockwise to lower the fuel level.

[ratsnst1]

Originally Posted by Voyager

I’ll lower the fuel levels. Stupid question time - to lower the fuel level in the bowl, do I lower or raise the float? I experimented with raising and lowering the float in the rear bowl and could not see the fuel level consistently move up or down in the sight glass.

Yes - black smoke when I restart the car.

I’ll verify the fuel pressure with the engine installer.

I’m loving the motor…

have fire protection when your doing your carb stuff dude .

[ratsnst1]

If you have a electric fuel pump, key the ignition turn pump on and do it that way cold.Also bleed your carb down low then build it up much easier.with the engine turned off.

[Calbullet]

FWB when you turn the adjustment screw clockwise, you are lowering the needle/seat lower in the fuel bowl and lowering the float also. with the float lower, less fuel will be needed to push the float up and close the needle/seat.

[mattpatt]

Just found this thread. According to Quick-Fuel the fuel level sight windows should show the fuel level half way up the window. I'm having a stumble problem on hard braking (KC all aluminum 427 (351W) with QF 780 carb).

I'm confused (info in this thread and the QF site info not the same).

Can anyone clear this up?

Many thanks!

[WardL]

I get an engine flutter when taking a hard turn. My levels were in the middle of the plastic float windows. I think I need to lower them. The plastic float windows are intended for temporary use only. I had the plastic windows in my carb when I purchased it used and when fooling with the floats found they had dissolved to the point where they were about ready to leak and quite dangerous. Only use the clear plastic inserts for adjustment. Once the floats are set where you want them, put in the brass inserts for normal use.

[Voyager]

Wow – back from the dead…

I lowered the fuel level to ½ or so. 2 years and 3500 miles later, it still threatens to die if I jam on the brakes real hard (near lockup). I blip the throttle in-between downshifts to keep the revs up. Since I’m not racing, it’s not really that big of a deal.

Was not aware the site windows in Quick Fuel carbs were for temporary use only?