I have a power washer from Sears with a Briggs & Stratton 5.5HP motor, Model: 580 767202

Recently I've noticed that with the engine and water running, the power washer loses power once I release the trigger and press it again. The motor continues to run and the water flows through the gun but without power. To reset the water power I need to disconnect the washer tip attachment from the gun handle and squeeze and release the trigger once to allow the motor while running to "reset". I replace the power tip and squeeze the trigger again, and it powers up to its normal operating pressure of 2250 psi until I release the trigger again.

Any suggestions are greatly appreciated.