i have a 14''eager beaver cahinsaw 2.0?

it ran great all year now today it dies !it starts up and runs but when i rev it high it starts to stall and die at will stay running for a min but then if i rev it high it will start to stall but wil lstay running if i keep it low then ill start to rev it high and will last a min then go back down and all most stall again how can i fix it they dont make parts anymore for it is there something i can do it still runs ....