What the hell is this?

Please see the picture. I dont know what this pipe is but it contains 2 stroke oil in it and everytime i plug it into the upper left one it stops the engine. The upper one is next to the fuel line.

This is on a PGO big max 50cc

please help, it seems to run fine without it connected.

http://farm5.static.flickr.com/4097/4785904049_1134476297_b.jpg

It is from your oil pump.
If you leve it un connected. You will destroy your engine.