Bookie,


If you mean the pressure nipple, that is screwed into the right-front side of the crankcase and connected by a flexible tube to the nipple, in the bottom part of the carburettor, on the opposite side from the needles; it operates the carburettor's diaphragm pump.
It is supposed to be sealed by a fiber washer; not with glue.

It provides pressure/vacuum pulses, of mostly gaseous medium, but an occasional drop of gasoline may get there too, from the crankcase. If gasoline appears to flow into the tube from the carburettor, the pump-diaphragm could be leaking.

Could the ignition sensor have moved, changing the initial ignition advance of the engine, causing it to back-fire?