I have two HT75s, both cut well. One, however, bogs when I throttle it up from an idle. It has a Zama with only the L mixture screw. I have ultrasonically cleaned and rebuilt the carb, and it pressure-tests just fine. I have pressure-tested the engine, checking for air leaks, and found none. It starts easily and runs and cuts great, but I have to slowly bring it up from an idle to full throttle. What am missing? Any ideas? Thanks, T-A