Although I don't disagree with Randy on the cost benefit of purchasing a Facet pump over that of an SU, I have had my original SU pump running strong for the past 52 years with only minor issues. I am not sure that I agree with Bob and believe your diaphragm appears to show some contaminants from your fuel that may have caused the pump's valve to stick open. Fuel agitation as a result of the open valve could be the source of the whirring sound and could be blocking the tick and eliminating delivery.
I would clean out the pump and readjust for good flow. Additionally, if you have a points-triggered pump, I would clean the points and remove any electronic component connected to the points (SU placed diodes across the pump points to eliminate point flash but it didn't work all that well). I would then install a Transient-Voltage Suppression (TVS) Diode that will eliminate point flash and burn to make the points last almost forever.
As most are unaware, the SU pump depends upon a coil for operation. Many have not realized that this coil has the potential of raising voltage across the points to as much as 200 volts and is the primary cause of point flash and/or burn. A P6KE20CA TVS (manufactured by Vishay), at a cost of around $1.00 or so, will allow up to 27 volts to pass across the points and shunt to ground anything above. The 27 volts is sufficient to burn off point corrosion formed during long periods of inactivity and/or storage but well under that needed to cause point flash or burn. As a result, I have found no need to replace points or do any maintenance on my pump since installing
Yes, if you are going to replace your pump, the Facet pump is both reliable and much less expensive then a new points or electronic SU pump. However, I would first consider seeing if I could service the SU pump back to performance before a replacement.
Just my thoughts,
Ray(64BJ8P1)