I have recently had problems with the float bowls on my 80s Nikki randomly overfilling. It can happen at anytime, even while driving (noticeable by a slight stumble while at cruise, then it stalls with the clutch out). I can sometimes restart it, but usually I have to pull over and tap the air horn banjo bolts.

The problem was apparently sticky needles. I finally opened the air horn up and low and behold... no retainer clips! That is the first obvious thing I noticed. It causes the needles to randomly jam up and overflow the bowl with an erratic drip of fuel. I can fix this by finding some clips... BTW The carb was sent out to be rebuilt professionally by a shop about a year and a half / 1000 miles ago and cost the original owner $800!!

But possibly related, I also noticed that I am missing one of the springy looking assemblies near the front float. Is this required? It seems like one of my old carbs had two, but this one only has one. I borrowed a picture from a fellow forum member

 

Thats an 80 SA Nikki (cause I know its DDs carb) but later carbs I don't think have those spring
things in them. Curious to know the answer.

 

Those long springs could be part of the power valve circuit found on automatic trans models. Anyone know for sure?

 

There is like a little shrewder valve in the rear float bowl that it connects to. Car is 5 speed.