Karcher 2020B?

My Karcher suddenly raced and the water stopped although the pump was still running. dismantled the outer case and the works are all sealed up in a nylon case, so no way of getting in, so binned it and bought a new one at a third off at Wickes, well, it's rubbish, no power to the spray, should have returned it but will not buy Karcher again. Why did the old one have more power than the latest model.