How to Repair a Gibson Mower

Ensure there's gas in the Gibson mower's tank if it does not start.

Drain the oil filler completely if you accidentally added gas to it. Remove the oil and gas mixture completely before attempting to run the Gibson mower again. If you have already begun running the Gibson mower, immediately cut it off once you realize your mistake. The mower will immediately make quite a mess, so cut the engine before any permanent damage is done and clean up the mess before draining the mixture. Cutting the engine immediately and replacing the oil should save the Gibson mower from any lasting complications.

Open the plastic cover of the Gibson mower in order to access the engine assembly if the mower won't run but gas and oil levels are appropriate.

Remove the Gibson mower's plug wires from the spark plugs. Follow these wires to the rear of the engine assembly where the magnetic coil is located.

Find the thin, black grounding wire that sits beside the magnetic coil. Remove this wire from the plug it connects to that sits to the outside of the flywheel. The flywheel is the circular part that lies directly behind the coil.

Hook one of the plug wires to an old spark plug for testing. Turn on the Gibson mower and check for any sparks. These sparks should be blue or white in color. If the sparks are "weak" and are yellow and orange instead, you will need to replace the magnetic coil entirely. This part can only be supplied and replaced by the manufacturer, so prepare to take your mower in.

Measure the Gibson mower's air gap if the plug produced no sparks at all when you attempted to run the machine. The gap may have increased in size incrementally, which can cause the engine to fail to start. The gap is supposed to be between 0.010 and 0.015 inches in size. Measure for this.

Loosen the coil in its place by using a wrench if the air gap is too large, then apply slight pressure on the outside of the coil and the flywheel right behind it. This should close the gap incrementally enough to make the repair.

Turn on the Gibson mower again to test it. Sparks should now fly. Tighten the coil back into place, replace the plug wires into the spark plugs and set the engine cover back into place.