Firstly confirm it’s tuned correctly or
at least within spec. Confirm metering lever height and that the impulse and fuel line are air tight. Put a new fuel filter in. Try saw again. If no better then run a pressure and vacuum test and test all three oil seals and that the oil worm gear is seated correctly. Test the lower o-ring on adjustable oiler lever, the o-ring within the oil pump and the rubber grommet on the oil pump. If they check out, check all the gaskits between the carb and the cylinder flange and the gasket between the muffler and cylinder flange, the cylinder gasket and case gasket.
if they check out fine, then test the spark plug threads, decomp and threads at the top of the cylinder and the bolt at the side of the cylinder.
If they all check out fine, check again because one of them is leaking.