The hose that comes out of the bottom of the manifold and connects to the crank case. I found a big hose leak in that and when the motor coughs smoke comes out. What is the purpose or function of the that hose. I thought if was like an over flow for oil and if just put it back into the cylinders. I found several small gas leaks in other places and fixed them. It seemed to get a little better but was wondering if the one on the manifold that it coughs smoke out would let extra air in the cylinders. ALso I noticed when the motor would cough I could feel it pull gas by holding onto the primer bulb. It is alittle better but want it to go away. If you think the place where it is coughing smoke would cause it to run lean then I would reclean the carbs again. Oh ya it still coughs when I hold presser on the bulb so I guess it is not the fuel pump but I put a kit in it anyways.