Small Engines (Lawn Mowers, etc.): honda ht3813 ride on, honda ht3813, dip stick

Question
Hi Eric my honda is having bit of trouble at the moment when it starts it starts fine pushing out plenty of rpm but after 2/3 minutes i can hear it losing rpm to it gets to a stage where you can still drive around about half speed but if try cutting it will stall
i once over filled the oil and when i started it it blew a lot of smoke ,so i empty sum out up to the full mark on the dip stick,
i have changed the spark plugs twice,   i empty out fuel tank blew out  fuel filter

Answer
Have you removed, disassembled and cleaned the carburetor with compressed air from an air compressor and carburetor cleaner?

You problem sound like the high speed circuit on the carburetor is not working correctly.  Most likely the small ports on the intake side of the carb are clogged with some debris.
Start with cleaning the carb and let me know how it runs after cleaning.
Eric