I just got my first four stroke. An OS 120 with pump and no manual. The connections to the pump are where I am having problems. I have found out that there is an in ( imagine that) and an out to carb-see attached photo-and a connection from crankcase impulse. The main problem is there is no place to connect the unused nipple to get this crankcase impulse. I know these connections are old hat to some of you and I need HELP. I have also found out that the fuel tank is not a pressurized system but a ventilated one.

Pastorjody,

Couldn't find your picture. However I had an OS 120 with the pump, but it was a pre surpass. The pump was driven off the crankshaft. It had three connection points: tank in, out to carb and the third was a recirculation to the tank. This provided a pressure relief at low fuel flow to the carb. I don' know if yours has the same setup.