new member with a sick Rancher 420

The beast will start and idle fine but dies when given throttle and typically has a backfire. What I've done so far: 1. disassembled the fuel pump assy and replaced the filter, it was filthy..... NO JOY!. 2. After further thought and research, I purchased a new OEM fuel pump assy. NO JOY!. Starts, idles fine, backfires and dies with application of throttle. 3. Watched the FL red light flash 1 time followed by 8 flashes.... 1-8 trouble code? It's been doing this all along....I just was not smart enough to pay attention. OK, maybe I'm getting smarter(or not). But this code is not listed in the manual. Any thoughts??? Any help is appreciated.