How do you change the gap on a spark plug?

Answer 1

First, any time you put a new spark plug in, even if they tell you that they are pre-gapped always check them.

There are different tools available, the simplest of which use wire of different gauges to measure the gap and one or two small notches in the tool for grabbing the spark plug tip and bending it to get the right size gap. One of these tools is round with wire loops around the edge and the other is like a set of feeler gauges with each gauging wire on its own swing-out arm.

At the correct gap the gauging wire should slip in and out of the gap with slight friction, not freely. When bending the tip, do it carefully. It should barely move.