How do I Replace a Solenoid for a Briggs & Stratton 18 HP Lawn Mower Engine?

Contact your lawn mower's manufacturer or visit a local lawn mower parts store to procure a replacement solenoid for your specific mower model.

Turn the Briggs & Stratton engine off and allow it several minutes to cool.

Open the engine cover over your lawn mower and find the battery. The rectangular battery box will have the two distinctive, positive and negative terminal wires on either side. The positive wire is red and the negative is black. Loosen and remove both terminal wires from their connection points on the battery by using a socket wrench.

Trace the red terminal wire back to where its other end connects to the solenoid. The black terminal wire also leads back and connects to the opposite side of the solenoid. Use your socket wrench to loosen the bolts each wire is connected to so you can disconnect both.

Look over the collection of small wires that cover the Briggs & Stratton engine's solenoid. This wire harness is fastened down by a retainer clip. Flip this clip upward by sliding a knife or similar flat tool underneath it and prying upward. This will disengage the clip and let you remove the wire harness.

Loosen the bolts on the solenoid by twisting each counterclockwise with your socket wrench.

Pull out the solenoid and lay it aside. Slide the new solenoid into its place.

Follow your operations in reverse in order to reattach the solenoid's bolts, wire harness, and the battery's terminal wires.