Okay, so my problem right now is if I'm holding it open running ~4800-4900 rpms it will stay clean and strong for 5-6 seconds and then either backfire or if I keep holding it, just shut down completely. To restart it, I have to primer it (manual fuel pump) with a few pumps and then it'll fire right back up. I was thinking the fuel pump could be going out because of the shut down, but would that also cause it to backfire?
Thanks.