The pump Im talking about is built into the fuel filter assembly. Im wondering if it has a bladder or spring that could be getting sucked down a bit and shutting off the fuel supply partially. There is no resistance when pumping it and just trying to eliminate potential problems. The skid steer starts ok but then after running about 40 seconds or putting under a load it starts running rough and seems starved for fuel. Has no power when increasing the throttle. Just a hit or miss till I can find someone local to work on it. Having a hard time with that.
If it's a pump built into the filter housing, i feel this is a priming pump, not the actual lift pump.
Still, an inline pump is a good idea for testing, when the machine bogs down, get out and give it a good squeeze and see if the engnine picks up, if it does, your lift pump is probably bad.