mustang69

Hello everyone. I have a 1988 350 moto 4 that starts and idles great. My problems is when I try to rev the engine it just dies. If i ease on the throttle it will rev but it sputters and will backfire through the carb. I have cleaned the carb and put in a new spark plug. I did notice the spark was orange and looked a little weak. Any help would be greatly appreciated. This thing has me ready to pull out the rest of my hair!