Does it seem to try to start when turning over, like attempting to fire up and failing, or does it just turn over and that it? How did you check for spark? You mentioned that you were getting spark, so that's why I ask. You getting spark at the coil, at the plug? Technically if your getting spark at the plug and getting fuel, there should be combustion lol. If you can clarify a bit for me I believe I can help you find the culprit