old 3.5 engime gets fuel only when carb wide open

[nitrorc5]

my k&b inbored engine only gets fuel to the carb when it sopen more than 3/4 throtal
the lines are an inch above from carb
i think that when i try and start it sucks in unless the carb is open?whats with that
is the pressur nippal on the back lower part of the engine messed up
the tank has no holes the lines are new and it did run good in idal out side of water after i cleaned it two weeks or so ago
i did make it so that it has two lines on the tank cap insted of having the pickup line on the bottom becouse it was geting air and would lean out
the carb is at 4 turns out
can you help me

robrto v

[nitrorc5]

thank u for reading but i figuerd it out the problem that nippal i talked about was cousing the problem
i thouth that that was wath pressuered the tank it didnt
a person at my local hobby shop told me that that nippal was used in the 80's to give more power too the engine with two tanks
so i put a nippal on my exhoust two pressur the tank like most cars and plians have and know it works great and has realy good excelerating reponce