18.5 intek b/s engine.
Sometimes hard to start, when running it smokes out exhaust.
Also smoke coming out of fuel pump vent hole.
Runs better at full throttle but w/more oil from fuel pump coming out.
Oil level is not overfull, any solutions?

What is a Fuel pump vent?

First thing I would do is check the valve clearance?

Sounds like you have a gasket or seal leaking some where causing too much internal pressure.the fuel pump works off engine vacuum.pressure is forcing oil through the pump breather vent,