When pumping, pause at the top and bottom of the stroke. Especially the bottom. Take your time. You will use about 1/3 less strokes than if you didn't pause. Once you get up to about 100 strokes, I would pause. Let the pump cool down. Pausing at the top and bottom also helps with the pump not heating up so fast.
Also, on the down stroke, have your arms be stiff (not bent at the elbows) and use your weight.
Welcome to PCP's.
Chas