Have a 84 nikki I rebuilt accidentally threw old needles away when I rebuilt it. Used the suggestions on this forum for burnishing the new needles. Floats arw set to FSM. When car is not running with fuel pump on the needles don't leak but once I run the car for a few miles and shut it off then the needles dribble out of the Venturi's . Carb is modifies nikki per sterlings instructions front venturi seem to be the problem as it causes the front rotor to run rich. Floats are not stuck as I have tapped on them with no change to the dribbling. Is there a way to get the needles to seat better? They are not sticking, I believe they just unseat themselves after car has been running

 

The "needles" do not leak into the venturis. They fill the bowls. If they are leaking, then the level in the bowls will increase. Once the fuel pump is turned off, there is no longer any pressure to push fuel through the needle valves into the bowls. So, assuming the bowl levels are correct when you turn off the fuel pump, there is some other pressure imbalance that is pushing fuel through the jets into the venturis. I suspect that the bowls aren't properly vented and you have built pressure in the bowls which can then push fuel into the venturi. The bowl vent valve needs to be open during operation or completely disabled in the open solution. You might have another problem, but I would look at the bowl vent valve closely.

Carl

 

Bowl vent has been disabled and removed

 

Once I turn fuel pump off the venturies continue to dribble for a bit into the intake

 

Without the vent, the bowls can build pressure and leak during low vacuum.

 

i do have an extra tophat with a working vent. so your saying i need the vent working to not flood? i thought that removing it and bieng open all the time is the way its supposed to be?

 

Unless I am remembering incorrectly, the vent in normal operation is open when the ignition switch is on (i.e. power to the valve) and closes when the ignition is off. I believe the original reason was to prevent fuel vapors from escaping to atmosphere with the engine off. As such, if there truly is a clear path for the bowls to vent all the time, that should not be your problem.

In my race car, I had problems for a while with the fuel getting too hot and boiling in the bowls. This was usually a problem after coming to a stop (pit stop, on-track spin, etc). The boiling seemed to be a combination of excessive heat into the fuel tank from the exhaust and excessive heat into the carb from the header. Several iterations of increasing insulation of the fuel tank and carb from heat sources eventually solved the problem. Don't know how that info might fit in your situation, but.......

Good luck.

Carl

 

Just looked at your previous thread on flooding while in operation and you said you removed the vent valve and plugged with jb-weld. You need to make sure that the vent path from the bowls to atmosphere is open and not plugged with jb-weld. I am guessing you already checked this, but can't hurt to confirm.

Carl