How to Install an Engine on a Walk Behind Mower

Remove Existing Engine

• 1

  Place a small container that is capable of holding the gasoline remaining in the mower fuel tank under the fuel line fitting of the tank. Remove the clamp from the fuel line that comes from the tank with pliers. Pull the hose off the tank and let the fuel flow into the container. Note that if the engine still runs and the fuel tank is almost empty, run the engine until it quits to burn any remaining gasoline from the fuel tank. Let the engine cool completely.

• 2

  Pull the spark plug wire straight off the spark plug and let it hang. Pull back slightly on the engine pull cord, then slide the cord out of the looped bolt on the lawn mower handle. Let the cord slowly retract into the engine.

• 3

  Lift the side of the lawnmower upwards 90 degrees to reveal the underside of the mower deck. Hold the cutting blade with a gloved hand while loosening the blade retaining bolts with a wrench. Finish removing the bolts by hand. Pull the blade from the spindle under the engine and place it aside.

• 4

  Locate the engine retaining bolts on the underside of the deck. Loosen the bolts with a wrench. Keep the engine from loosening from the mower deck with one hand while removing the bolts by hand. Rotate the mower deck so that it is sitting on its wheels.

• 5

  Grasp the engine on each side and lift it straight up from the mower deck. Remove the engine from the mower.

Install Replacement Engine

• 6

  Lower a replacement engine onto the top of the mower deck so that its mounting holes line up with the bolt holes in the deck. Hold the engine in place with one hand while tilting the mower deck upward to reveal the underside. Thread the engine retaining bolts through the underside of the deck into the engine mounting holes by hand. Finish tightening the bolts with a wrench.

• 7

  Place the mower blade over the spindle on the bottom of the engine. Hand tighten the blade retaining bolts. Finish tightening the bolts with a wrench. Lower the mower deck so that it is resting on its wheels.

• 8

  Pull the engine pull cord from the top of the engine. Slide the upper end of the cord into the looped bolt on the mower handle. Release the cord slowly until the cord handle rests against the bolt.

• 9

  Push the spark plug wire onto the tip of the spark plug until it snaps into place.

• 10

  Check the oil and gasoline and top them off before attempting to start the replacement engine.