Powerwasher runs, good stream of water but will not build up high pressure. What to do?

There will always be a stream of water unless there is a blockage, just from the water going in. Does the pump have a place to check the oil, see if it is good, ( not white) white shows a seal leak. Also is there water coming out of any other area, they have a pressure relief valve that if goes will not allow pressure till replaced. Also the unloader can be bad.