Found the problem. Using 10x magnifying classes I discovered a tiny piece of fiber partially clogging the high speed jet in the carb. removed it and saw functions perfectly.
Thanks all for your input.
Rick
It's 14in bar and chain, with a new chain on the saw. my elevation is 640' above sea level. I do sharpen the chains myself using an Oregon 511A. The rakers are angled low to high with the high end in front of the cutter. They are Sthil chains. I guage the rakers and grind them when necessary...
I'm having trouble with my Stihl MS180 C-BE chainsaw. The engine boggs down under a load and when just reving the saw. I have replaced the spark plug (properly gapped), rebuilt the carb, replaced the fuel line and the fuel filter, cleaned out the chain brake and the clutch and cleaned the fuel...