Abstract: A spark plug of an engine ignition/combustion system have the electrode gaps of the spark plug surrounded by a capsule having a controlled orifice system. The orifice system and electrode gap are positioned, sized, and oriented specifically for use with lighter-than-air fuel gas.

Abstract: On a work vehicle having a support, an implement carrying swing frame connected to the support by a first pivot pin apparatus, and an elevatable boom connected to the swing frame by a second pivot pin apparatus, a controllable locking apparatus having a boom lock for locking the boom in a substantially vertical position and maintaining the boom against movement, a swing lock for locking the swing frame against side to side movement, and an obstruction for preventing the swing frame from being locked against side to side movement unless the boom is locked against movement, is provided.