Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Hi, did you still need help with this? If so what is the model or part # of the carb?
What's happening is it's leaning out at wide open throttle due to the increased air flow from the K&N, this is real common. Some mikuni's have replaceable jets to richen the fuel mixture others you have to drill out the jet with a tiny bit and pin vise. if you can give me the part number of the carb or model number off the engine I can look into what type you have and advise further on how to procede.