Unloader valve followed by broken inlet or outlet check valves. Also have seen a few pressure washers, not Dewalt in these other cases but similar brand that makes the Dewalt where the key in the crankshaft comes out and the pump shaft doesn't turn.
#5
StarTech
And I had a bad venturi assembly on a AAA pump this year that no output pressure. First time I seen this.
Not had any with loss of pressure due to bad venturi check valves other than being stuck shut allowing no water flow.. Had had a few that would overpressure the pump and kill the engine when the check valve O ring split.. You can remove the check valve and keep using the washer It will operate fine without it.
