How to Troubleshoot a Kohler Pro 20

Find the spark plug on the right side of the Kohler Pro 20 engine. This small plug has a thin ignition wire that connects into its back. If this ignition wire has become disconnected, the motor will not run. Slide the ignition wire into the rear of the Kohler's spark plug.

Replace the spark plug if it is old or it shows visible corrosion on its end. A bad spark plug will keep the Kohler Pro 20 engine from starting completely. Disconnect the ignition wire from the bad spark plug and remove the plug entirely using a spark plug socket on your socket wrench, making sure you first clean around the spark plug so that dirt doesn't get into the engine upon removal.

Consult your Kohler Pro 20's manual to discover the proper kind of replacement spark plug to use.

Measure the gap between the two electrodes on the new spark plug's end using a spark plug gauge. The two electrodes should be around .030" apart, but consult your Kohler's manual for the exact specifications for your engine. Use the spark plug gauge to gently bend the curved electrode if necessary to change the gap between the electrodes.

Install the spark plug using your socket wrench with attached spark plug socket, then reinsert the ignition wire into the new spark plug's rear.

Attempt to start the motor. If the Kohler engine still refuses to run, check the solenoid's wires. The solenoid can be found behind the machine's battery. Follow the battery's red and black terminal wires from the battery to further back on the engine. Each wire will come to rest on opposite sides of the Kohler Pro 20 engine's solenoid, where they should be connected to a single bolt on each of the solenoid's two sides.

Tighten one or both of the terminal wire's back over the solenoid's bolt(s) if the Kohler Pro 20 engine still won't start. Place the open end of each terminal wire over each solenoid bolt and tighten each by twisting the bolt clockwise with a socket wrench once the terminal wire is in place.

Check the Kohler Pro 20 engine's carburetor if the mower is running harshly or if it starts but is "winding out" and failing over time. Find the carburetor bowl on the left side of the engine. This distinctive bowl on the Kohler engine will likely be leaking from its bottom nut if the motor has been running harshly. Place a pan under the nut if fluid is leaking out.

Loosen the Kohler Pro 20 carburetor's nut using your socket wrench to drain the carburetor. Wait until the drainage completes before removing the pan. Oil and excess fluids may have leaked into your carburetor if you tipped your mower recently to drain gas or otherwise manipulated the level of the mower when performing repairs without draining the oil first.

Tighten the motor's carburetor nut back into the bowl using your socket wrench.