stalling

Got my old three wheeler out and running again but when it gets warmed up it will stall out and not start back up till after a minute or two any ideas as to what could be going on would be great thanks I have rebuilt the carburetor and checked fuel flow spark and that is not loosing spark...

I am trying to figure out a problem I am having with my fuel pump on my 89 TRX350D. At first the 4wheeler started stalling out and I could not hear the pump running. I replaced the pump with a Mr Gasket low pressure pump but it runs all the time when the key is on. The oem pump never did...