Hi, I'm having what I think is a Carb issue with my 1975 6hp outboard. first started at full throttle where the motor would lose power then re-gain it intermittently. I have since removed the carb and lower bowl and tried to clean it. used compressed Air to blow through inlets. Put it back on and fired it up ran great for 15 Mins at low speed while I adjusted the low speed mix.Then when tried to open up the throttle and rpm went up a bit and it started to smoke heavy (more than normal) started to stall when a tried to reduce the throttle. The only way I got it to run nice in this state was to shoot some compressed air in the carb? any advice?