My motor seems to run fine at quarter throttle, but when I try to get on plain at all or any more throttle it bogs, when I back off again it runs fine. When in neutral it same outcome. I've checked all coils and plugs they all fire at 3/8 of an inch. I've cleaned the carbs and I've ran the tank empty and put the perfect mix of fuel in. I even tried straight gas to clean the engine out (only a carb bowl full) no worries but even then it did the same thing. Any ideas or helpful clues.