I would pull the main tank, empty it, clean the screen on the pickup and re-fill with 2 cycle oil. Best de-carb I know of is to squirt 4-5 shots of Marvel Mystery oil from an oil can into each sparkplug hole, let set overnight before running, then start adding Sea Foam to the fuel. Don`t think I would try to empty and clean the motor reservoir unless you have a way to suck it out, then refill with 2 cycle oil .
“The world will not be destroyed by those who do evil, but by those who watch them without doing anything” Remember what He has done and remember that He is not done yet! GOD IS GOOD