Millermatic Mig Welder

Millermatic 185 mig welder 09-06-2011, 0200 pm.Using the mm185 w argon25 co2 shielding gas, i have for a long time had problems w my welds excessive spatter porosity.I have a hunch that the shielding gas isnt even getting to the weld sites.In general, i try to.