Like joew sez, run it without the filter and see. It helps to have a clear gas line too. Hope you tried to rinse the tank out first. I had sandblasting crap in mine, blew out a ton with air, then did a strong water rinse, more air and a hot blow dryer. I ran an external filter just to be safe, make sure your petcock screens are clear too, thats a fine mesh easy to get clogged if you have junk in the tank. Most fuel filters flow only one way too...make sure it's correct. Good luck.