Help...Holley problem / Gas out vents...

[rpoz11]

Breaking in the motor and I have gas pouring up the vent tubes. Im not Holley literate and need assistance on resolving this issue...

[GTO_DON]

floats are stuck or set wrong...

[rpoz11]

We are working on setting the front and rear floats...however, we backed the set adjustment counterclockwise and are still experiencing too much fuel.... Can we back these up too far where we are defeating our goal?

[VintageMusclecar]

Assuming the fuel pressure is normal...

Sounds like the carb has some trash stuck in the needle & seats. If they're externally adjustable needle & seats (big screw & a 5/8" nut on the top of each float bowl), the fix is pretty easy. If they're internal, the carb will have to come apart.

With the engine off (obviously)---

External:

Put a shop rag around the needle & seat adjustment screw & nut on the top of the float bowl. Use a large screwdriver to break loose the lockscrew just slightly, then turn the screw & nut counter-clockwise to remove the assembly. You may have to use a 5/8" wrench, but it should thread out by hand.

Take a can of carb cleaner and give the needle & seat a good blast, paying attention to the little tip on the needle and its seat. Give it a good blast of compressed air afterwards to make sure the debris is cleared. Make sure the needle travels freely up & down. Look for any cuts or other damage on the tip of the needle. If you see any damage, it's time for a new needle & seat. Also look to see if the rubber "O"-ring is torn or damaged. If not, you can re-install it.

Place a light smear of grease on the rubber "0"-ring and reinstall it in the carb. Using just the adjuster nut, thread it down until there's maybe 2-3 threads on the needle & seat showing above the float bowl. If your original gaskets (1 under the nut and 1 under the screw) survived, you can re-use them.

Thread the lock screw back in place and hold the nut with a 5/8" wrench and tighten the screw securely. Don't get carried away, just snug it securely.

Repeat for the other float bowl.

(Before you do anything else, find out where the trash came from. Do you have an inline fuel filter?)

Start the engine, and if you still see gas spraying from the vent tubes, it's time for new needles & seats. If not, then you can re-set the float levels after the engine has finished break-in. Just make sure the engine does NOT go lean or overheat during break-in. (breaking in new engines is hard enough w/o having to deal with a finicky carb in the process )

Once you can let the engine idle, remove the sight plug on the side of the float bowl. Again, wrap a shop rag around the needle & seat and with the engine idling, BARELY crack the lock screw loose. Use a 5/8" wrench to raise or lower the float level (clockwise lowers the float level, counter-clockwise raises it) until you just see fuel start to dribble from the bottom of the sight plug hole. (If the fuel level is high to begin with, you'll need to let the engine run for a few moments to run off some of the fuel in the bowl.) Once you see it dribble fuel, hold the ajduster nut securely and tighten the lock screw back down. Repeat for the other float bowl.

If the carb has internal needles & seats, the float bowls will have to come off to fix it. Let me know if this is the case and I'll try to walk you through it.

Eric

[GTO_DON]

your probably going to have to pull the bowls to see which way to start with. then take out the side screws, start the car and adjust them till gas starts to trickle out. but be careful!! you dont want to start a fire! just the way i was shown how to do it years ago.

[rpoz11]

Here's what I have: 3310 780 model 4150. We have further tried(while running in and out of the house to catch up here) to adjust up and down that float but fuel still seems to flow out of the vent tubes...

[rpoz11]

oh, AND this carb has been gone through and rebuilt as well as recolored if that helps....This is just such a unexpected issue...

[VintageMusclecar]

Don't feel lonesome, it happens to all of us at one time or another. It really sounds like there's trash stuck in the needle & seats that's not letting them close.

Try cleaning them like I described above and see what happens. I'll check back in a bit to see how you're doing.

Eric

[rpoz11]

Do you advise that I remove the bowls for this??

[VintageMusclecar]

Shouldn't be necessary unless a LOT of trash has gotten into the float bowls...this could plug up a jet.

Just pull the needles & seats and clean them, then see what happens.

Eric