Quick follow up to this old problem. My Accelerator pump check valve which is factory set and not to be adjusted, was leaking. Changed out the assembly and it leaned out the full throttle excess rich problem to a more normal slightly rich at full throttle. Explains why local carb repair attempts failed because it was not possible, or obvious to me, to test the 'accelerator relieve valve. I assume the during a carb repair, this part is not generally replaced unless it gets to a facility that can fully test flow the carb and they find the problem.
