Well i noticed that when i hit the brakes hard and came to a stop it would stall out. So I adjusted the float level, nothing, lowered the fuel pressure, nothing.

Then Ran it with the carb box off
Every second or 2 a drop of fuel forms on the booster (i think is what its called the little ring that is in the middle of each barrell of the carb) then the drop falls into the motor. What causes this and how do I fix it???

Its a holley 750 DP.

"Edit"

This only happens on one of the secondaries. so I guess that makes it a little harder to figure out.

 

come on guys no one? im stuck on this one and need some ideas

 

Are you talkin about the venturi? I have no clue of wha to tell you to do as far as fixing your problem. But maybe useing the right terms will help someone in the know understand your problem a little better. Good luck.

 

Is this with the car on or off? I would think with car on you would never get fuel just dripping from there, it should be spraying. If its with the car off than too much fuel is getting into your bowls. I would lower the float level or check your needle and seat making sure it is working properly and there is no gunk in there.

 

sounds to me as the float is too high, or you possibly have a partially sunken float. idtry adjusting it down a little bit more first.

 

what mods have been done to the carb??

 

What's your fuel pressure set at? High fuel pressure can overcome the needle and overfill the float bowl. Brad

 

Can a solid float sink? I thought they are indestructible?

Carb is a 750DP milled choke 73 front 90 rear jets with jet extensions .0925 pcvr 4.5 power valve. .120 needle and seats and nitrile floats. It does it with the car off but running its not quites as bad but it still happens. Ive tried adjusting the floats down another full turn from where they were. no good and adjusted the regulator all the way out, and its only adjustable from 4.5-9psi so the carb cant be getting that much pressure, the fuel pressure behing the regs is 14psi.

These are through two holley regs with a boost port added, one reg for eash float bowl. the front of the carb seems to have no problems and this only happens with one barrel of the carb I could understand if it were both rears but only one???

 

When you adjust the floats do you see it move down. You could have the float all the way up and even though you turn the screw in one turn it will not move. I would look thru the float sight level hole and make sure you see some movement in the float downwards as you turn. If you turn the screw as far down as possible and you still see no movement of the float than you know something is physically wrong with the needle and seat or possible the float lever.

One thing you can do is try and get the level of gas below the sight level hole. If you get it there and you are still getting a dripping problem than it is something else. You should be able to get it at that level and watch it for 3 minutes to make sure the fuel level does not creep up.

PS: All these tests should be down with the car off or you will get a gas shower.

 

The stalling out is typically a high float level issue
but could be caused by your vent whistles not being the correct length. You want the rear plastic whistle to be about 2/3 of the length of the front
bowl whistle. Carbs without any whistle or the tin baffle will get fuel slosh into the venturis on rapid decels. Yes, Nitriphil floats will sink and are not indestrucible, they just will not collapse.

The drip on the booster if it is up high may have come from the vent tube and was just there.

If it is on the sheer edge of the booster it typically is a float level issue.

Tom V.

 

I have to play with it later on today after i change out a leaky fitting on the fuel pump. BUt somone also told me if the idle is adjusted to fast and the therottle plate is cracked opened to far this will draw some fuel out of the booster where it should not come at idle, however i can get this problem to occur with the engine not running either so that rules it out i guess. Im kinda just ranting so ill let you guys know when ive solved the problem

Thanks
Mike

 

Ok so i lowered the fuel pressure and float level. The carb no longer drips gas out the boosters but still stalls when breaking. However not in the begining of my test drive only about 10-15 min after begining.


I took the lid off the carb box and noticed some gas puddling in the bottom and the tops of the boals were wet.

However i cant get it to flood like this in the garage to see whats happening.

heres the big question my fuel lines and regulator are close to the downpipe, is it possible that the heat causes the fuel to expand after the regulator and increase my pressure?????

The downpipe is unsheilded and the Regs are mounted about 2.5 inches directly above it. Also the lines go above the downpipe. Maybe some headerwrap would solve the problem?

 

You might still need to bring the rear float down. I was having the same problem with the rear float adjusted correctly, just below the sight plug. A half turn farther down cured it.