Ok, cleaned the carb, put a new plug in. Got her all cleaned up and put back together. Last night filled a garbage can with water and put her in. Took about 6-8 pulls and a spray of starting fluid, but she fired up. Ran ok, not great, but ok, till I tried to throttle down. Bam, bam, backfired through the carb and died. Started a couple of more times, same thing. Got her running and cut the high speed screw way back, did not seem to affect high speed operation, but it did allow me to throttle down a little more before the backfiring started. Started a little easer then too. Anyone have any ideas on why I am getting the backfire through the carb when I cut the throttle back? Thanks.