You need to check your spark a little better. I have had several instances where the coil is not putting out enough fire for it to run, but still firing very weak. Take the coil wire off of the distributor and put a screw driver tip in the wire and hold it about a half inch from ground while someone cranks it over. Make sure The screwdriver has a well insulated handle amd keep your hand on it! You should see a nice crisp spark fromthe screwdriver to ground. Check the plug wires individually also to confirm fire to plugs.