Small Engines (Lawn Mowers, etc.): 2 cycle carb operation, exhaust muffler, new tank

Question
Hi Ben,  My son is now the very proud owner of a 2005 Yamaha Blaster,model# YSF200T w/a 200 cc 2 cycle engine. Had 2 fun days of operation. Now after a new tank of 40:1 mix ratio, the thing will not stay running, it will start but bogs down and stops running. checked the carb looks clean. Any help would be VERY appreciated.
Thanks in advance,
Tom

Answer
Tom
Is this a new machine? If it is bring it back,if not check the exhaust muffler to see if there is allot of soot and it may be clogged,then check the carb air filter and look in the tank to see what condition the fuel is in is it dirty full of partials etc etc.