Chainsaw Repair

I ran the saw without the chain and bar and can see the drive gear turning. The clutch itself isn't very old and is pulling fine. As far as the tube, after soaking it, I blocked one end and blew through the other and there are no leaks so it is good. The stone filter is clean and I can blow through it freely. These are aftermarket pumps. I understand longevity may not be the same as a factory pump but they should certainly be working when they are new. Anybody had experience with an aftermarket pump?