Surging is typically an indicator of a lean running condition. What to do about it?

• Check for vacuum leaks at the carb base. Spray carb cleaner around the base of the carb with the engine running. If you hear a change in RPM, you’ve found a vacuum leak.
• Check for vacuum leaks around the throttle shaft.
• Check for vacuum leaks around any vacuum-driven accessories and their hoses or pipes.
• Are your spark plugs medium gray/brown? If the are white/light, it’s a good indication your jet orifice size needs to be increased.