[prostreet64]

Been getting a little seat time with the new 463 and have noticed that if I get on it pretty good fuel will exit the vent tubes and then travel out the back of the shaker. Running with open carb at the present because I haven't figured out exactly what I want to do about an air cleaner setup; very limited space with the QF950 sitting on a Northwind intake with a 3/4 spacer. I can squeeze an 11x2 on top but that hardly works for street driving, certainly won't work at the track. My shaker is attached to the hood and can be removed pretty easily so when the car is ready for the track I will probably do that and run a tall air cleaner up through the hole in the hood or maybe a velocity stack. Anyway, I assume the fuel is being pulled from the vents because there is a low pressure at the back of the shaker? And as I get to a certain speed plus the effects of acceleration causes the fuel to leave the carb. Anybody else ever experience this situation?

[PAUL K]

Put spark plug boots on the vent tubes or make a flute style vent

[prostreet64]

Paul, do you mean that the extra height of the boots will solve the problem? Not sure about the flute style vent? Thanks

[Mike Davis]

The boot will keep the fuel from spraying out. Very common to see on cars at the track.
Here is the flute style vent. Buy them or make them.

[prostreet64]

Mike, thanks for the info. Makes sense now.

[PAUL K]

Originally Posted by prostreet64

Paul, do you mean that the extra height of the boots will solve the problem? Not sure about the flute style vent? Thanks

What Mike said. It's an airflow deal. When I went back to a shaker every pass over 140 would spray my windshield with fuel. I put the spark plug boot on to solve the issue.

[25stevem]

Your hood mounted scoop must not be truly sealed to the carb if the positive pressure at road speed off the windshield is being overdiden by under hood pressure.

Isn’t a scoop made that has a filter in its rear opening?

[prostreet64]

25stevem, my shaker is not in any way set up like the factory deal. It is for appearances only. No connection to the carb; none of the other parts are used, just the rear facing scoop.

[turbo69bird]

Check to make sure it doesn’t do it at rest w the fuel pump on , holleys are notorious for hanging up a needle and seat w dirty fuel and fuel coming up out of the vent tubes running pig rich. Just take the needle and seats out tap them a few times blow through them and put them back in it’ll clear it, but likely needed a better filter. Maybe not your issue but it is a lot of the time.

[Sirrotica]

This phenomenon is fairly common with no air filter in the rear facing scoop in a T/A. Again the carb was open and not sealed to the hood.

Years ago we had a 76 T/A setup the same way, with a high rise manifold, scoop bolted to the hood with a Q Jet. It did the same thing when the secondary air flap opened up. The gasoline would cover the center of the windshield at speed. It would also upset the fuel mixture of the engine, as it would lean out.

That air must be really turbulent to cause that problem. If I remember correctly an air cleaner stopped it.

I have no idea whether the air extractors in the fenders add to the problem, or not, been too long ago to remember the exact way we solved the problem.

Holleys have the same problem on a dirt track car, that they loose fuel out the vent stacks under hard left hand cornering. 90 degree spark plug boots pointed towards the drivers side of the car were the early fixes. Later on there were plumbing fixes that connected both stacks together and raised the height of the vents. Having used Q Jets on all my race cars, I've never encountered fuel slosh on auto cross, or dirt cars with a Q Jet.

Carters have the problem when going around corners too.

[prostreet64]

Quick update on this deal. Put 90* boots on the vent tubes with the boot facing forward. Made a few passes on the county road. No fuel coming out at all. Simple and quick fix. Thanks to Paul for the tip.