Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Don't have this engine or the carb, but when little engines doesn't seem to hold the fuel settings you set and nothing is moving, then likely you are getting bubbles in your fuel line. I have started installing little check valves to keep the fuel from backflowing, as especially on hit miss models, they sometimes can't afford a few cycles to prime the fuel again when it drops. Might be worth putting a flex tube fuel line to monitor for bubbles or backflow, until you can rule them out.