What does this mean? If it means that you take out a plug and the ground it and watch for the spark to jump the plug's gap, that is NOT a good test of spark. A spark that jumps a .035" to .045" gap in open air is in no way guaranteed to jump that same gap in a compressed fuel-air mixture. If it won't jump AT LEAST a 1/4" gap in open air, then the spark is not good enough. You have to test the spark right before you can rule it out as a problem.
