Disappointing dyno results

Worth checking the carb for changes to be sure, as well as the spark plug wires and spark plugs.
If the carb hasn't been touched then all its doing is responding to what the engine is calling for.
My guess will be one or more cylinders is not performing again. Not sparking, valve not sealing, ring ?
Again look at the plugs and wires, compare with plugs from the day before. If no clues there, then leakdown test.