This is driving me nuts. I grabbed my older Craftsman paint gun to primer a couple of fenders to see how far off the bodywork was. The darn thing keeps pulsing the primer out. I have taken it apart trying to find dirt or debris, checked pressure, readjusted back and forth, and still it pulses the primer.
Air pressure is consistent when partial trigger for just air, but as soon as the primer begins to flow, it is pulse, pulse, pulse.