Could very well be something got jammed in the pipe. There is normally a skimmer basket in place to prevent this from happening but if the prior owner had the basket out for some reason while the pump was running something could have gotten sucked in. Before you cut pipes is there any way you could rig a garden hose to some port and route the water backwards to the problem skimmer? If you do cut the pipe it's easy. When I need temporary adapters to do this sort of thing I don't even bother to glue PVC together. I connect the pieces and use cheap electrical tape over the joints. FYI a PVC 3/4" NPT male threaded adapter is close thread match to a standard female garden hose connector. Have to add another washer to the hose because it won't thread in all the way but it works for me. PVC is wonderful and cheap. You can mate almost anything to anything.
Al