Actually, I would do a few things. 1 new needles and seats and check pop off. 2 check for spark, if it is not getting correct spark I would check the voltage on the battery, we have had a battery just under 12v and it would turn over but never fire. Replace the battery and check the grounds on the coil. The problem is there is not one answer for you. You need to trouble shoot your problem eliminating one thing at a time. That includes compression test