I'm having a similar problem with my Nikki Carb on my Datsun 520 pickup. My original fuel pump is working, and it appears I'm getting fuel into the bowl, but no start except with starter fluid or pouring a little gas in the carb. I took the needle valve assembly off and the little spring, plunger and needle all just fell out. Is it suppose to be loose like that and just rest on top of the float adjustment? I suppose I need to look at the float level since ya'll said that "the float gets stuck on it if it goes all the way to the bottom". That could be, I suppose, what's stopping gas from going any further into the carb. I don't have a clear cover, so I can't see the fuel level. My main concern is that the needle valve, spring and plunger only seem to be supported by the float, and there's nothing else to hold them into the needle valve assembly. Is that the way it's suppose to be? it makes for tedious work if you're trying to put it back in with the carb already installed!