An electromechanical ignition device, the puff-jet, produces a highly turbulent ignition kernel that reduces ignition delay and burn duration. These properties, which are also exhibited by plasma jet igniters, should enhance the performance of vehicles run exclusively on CNG and facilitate the switch from gasoline to CNG in dual fuel vehicles. Results of preliminary bomb tests of the puff-jet have been confirmed using a motored single cylinder internal combustion engine. Compared with a spark gap ignition system, the puff-jet decreased both the ignition delay and the burn duration of methane charges and extended the lean misfire limit. Output power from the same engine run continuously on lean air-methane mixtures has been compared using the puff-jet system and a conventional spark plug. The puff-jet igniter was observed to increase output power when used under lean mixture conditions.