Today I tried adjusting my twin carburetor with a vacuum gauge. I followed the instructions on the shop manual and adjusted one carb to within 16-24 cmHg but the other carb won't adjust to within limit. It stays at 50 cmHg. Does this mean there is an air leak? Also there is smoke coming out of the exhaust on the same side as the carb with the 50 cmHg. What's wrong there? I'd appreciate any help.