Hydro Fan Balance??

Hi Folks. I bought an old QT16 with a Sundstrand 15 hydro. The cooling fan on the drive shaft is a plastic 4 blade with 2 blades missing on one side. The other two, and collar, seem fine. Would rather leave it be, than pull the shaft to remove it, but worried that it might damage pump by doing some sort of off balance wobble. Any thoughts?