How to Replace the Motor and Pump Assembly on a Ryobi Pressure Washer

Does your pressure washer fail under pressure? Does the motor just hum? You may need a new motor and pump assembly. The motor and pump assembly consists of a motor and pump (that are pre-assembled), a new pressure switch, and all of the necessary wiring. Common problems with the motor and pump assembly are motor failure (causing the motor to not turn on); a seized motor (causing the motor to hum); lack of pressure from the pump; water leaking from the pump; and oil leaking from the pump. If any of these symptoms occur, you may need to replace the motor and pump assembly.

Let's get started.

REMOVING THE MOTOR AND PUMP ASSEMBLY   1. Remove the soap tank.

a. Disconnect the soap dispensing hose from the pump.

b. Remove the nuts and bolts securing the soap tank to the frame.

c. Remove the soap tank from the frame.

  2. Remove the top motor housing.

a. Remove the screws around the entire perimeter of the housing.

b. Lift the housing away from the unit.

  3. Disconnect the switch.

a. Remove the four screws securing the switch cover plate to the underside of the housing.

b. Lift the switch cover plate away from the housing.

c. Note the location of the wires for reassembly.

d. Unthread the wire nut and separate the two wires beneath it.

e. Use long-nosed pliers to disconnect the BLACK wire from the switch terminal.

f. Use long-nosed pliers to disconnect the WHITE wire from the switch terminal.

g. Remove the pump and motor wires from the cover plate.

h. Remove the grommets from the cover plate.

  4. Remove the motor and pump assembly.

a. Remove the two screws securing the motor bracket to the frame.

b. Remove the motor bracket from the motor and pump assembly.

c. Lift the motor and pump assembly out of the housing.

DISASSEMBLING THE (OLD) MOTOR AND PUMP ASSEMBLY

  5. Remove the inlet/outlet tubes.

a. Use a screwdriver to pry the U-clip (surrounding the outlet tube) out of the pump housing.

b. Remove the outlet tube from the pump.

c. Use a screwdriver to pry the U-clip (surrounding the inlet tube) out of the pump housing.

d. Remove the inlet tube from the pump.

  6. Remove the gaskets.

a. Remove the upper gasket from the pump.

b. Remove the lower gasket from the pump.

c. Remove the two rubber bushings from the pump.

  7. Remove the grommet.

a. Use a pair of small scissors (or wire cutter) to cut into the side of the grommet on the white wire.

b. Remove the grommet from the wire (save this grommet for later use).

  8. Remove the wire insulators.

a. Remove the protective sleeve from the black wire (on the old motor). This sleeve should slide smoothly off the wire.

b. Remove the protective sleeve from the white wire (on the old motor). This wire contains a terminal connector, which will require you slowly work the wire (and terminal) out of the sleeve.

ASSEMBLING THE NEW MOTOR AND PUMP

  9. Install the wire insulators.

a. Install the protective sleeve onto the white wire (on the new motor). This wire contains a terminal connector, which will require you to slowly work the wire (and terminal) through the protective sleeve.

b. Install the protective sleeve onto the black wire (on the new motor). This sleeve should slide smoothly onto the wire.

  10. Install the grommet.

a. Install the grommet onto the new wire set. (The black wire should pass through the uncut portion of the grommet, and the white wire should pass through the cut portion.)

  11. Install the new foam seal.

a. Note: the foam seal must be purchased separately.

b. Peel the paper away from the adhesive backing on the new foam seal.

c. Install one end of the new foam seal onto the pump, and carefully wrap the foam seal around the assembly until the two ends meet.

  12. Install the bushings.

a. Install the two rubber bushings onto the new pump.

  13. Install the inlet/outlet tubes.

a. Align the notches on the inlet tube with the holes on the pump housing (the U-clip will pass through these notches).

b. Press the inlet tube into the new pump.

c. Secure the inlet tube to the pump with the U-clip. (A rubber mallet may be used to tap the clip into position.)

d. Align the notches on the outlet tube with the holes on the pump housing (the U-clip will pass through these notches).

e. Press the outlet tube into the new pump.

f. Secure the outlet tube to the pump with the U-clip. (A rubber mallet may be used to tap the clip into position.)

  14. Install the gaskets.

a. Install the lower gasket onto the new assembly.

b. Install the upper gasket onto the new assembly.

INSTALLING THE NEW MOTOR AND PUMP ASSEMBLY

  15. Install the motor and pump assembly.

a. Install the new motor and pump assembly into the pressure washer. (When correctly aligned, the gaskets should slide into the slots on the housing.)

b. Install the motor bracket over the new motor and pump assembly.

c. Secure the motor bracket with the two screws.

REASSEMBLING THE UNIT

  16. Reinstall the wires into the switch plate.

a. Pass the new set of motor wires through the center opening on the switch plate.

b. Install/reseat the grommet into the switch plate (securing the wires).

c. Pass the cord wires through the outer opening on the switch plate.

d. Install/reseat the grommet into the switch plate.

  17. Connect the wires.

a. Connect the WHITE wire (from the PRESSURE SWITCH) to the BLACK wire (from the MOTOR) and secure the connection with a wire nut.

b. Use long-nosed pliers to connect the BLACK wire (from the PRESSURE SWITCH) to the terminal on the on/off switch. (This terminal is located directly above the black wire from the cord.)

c. Use long-nosed pliers to connect the WHITE wire (from the MOTOR) to the to the terminal on the on/off switch. (This terminal is located directly above the white wire from the cord).

  18. Reinstall the switch cover plate.

a. Partially install the four screws into the switch cover plate (until the tips of the screws are visible from the bottom of the plate).

b. Align the cover plate gasket with the exposed screws on the bottom of the plate. (Use the screw tips to keep the gasket aligned.)

c. Tuck the wires into the switch box and install the cover plate.

d. Secure the cover plate with the four screws.

  19. Reinstall the top motor housing.

a. Install the top motor housing.

b. Secure the top motor housing with the screws.

  20. Reinstall the soap tank.

a. Install the soap tank. (The tabs on the soap tank should sit beneath the metal frame rails.)

b. Secure the soap tank with the bolts, washers, and locknuts.

c. Connect the soap delivery hose to the pump.