did some work on my f4 recently. Put her back together... Girl wont start. Has new battery, Starter is working. When I choke her and gas her to try and fire her up. It wants to go but just wont catch. I changed out the fuel, Im getting fireballs out the tail pipe, so its igniting but just wont runnnnnnnnnnnnn!. Please help me get on the road, please Im dying here.