Troy Bilt Model #3AQ609G063, 18hp B/S engine Twin II (model # for engine is42A707). I replaced the starter,solenoid, and it has a new battery. When I turn the key nothing. I jump the solenoid and the starter turns. I jump the starter and it turns. There is plenty of gas getting to the carb but, no fire from the plugs. Question is this... Do I need a new ignition switch? And, what's up with it getting no fire? It was working fine until the starter went out. Thanks...