i just bought a rz5424 zero turn rider the problems is the muffler is burning my lawn after stopping the mower for only 5-10 seconds I have many brown spots on my lawn the problem is with the bottom plate around the muffler is not deflecting the heat from the muffler away from the grass on one side of the muffler the spot is bigger because the exhaust outlet is on one side. the engine fan is pushing the hot air down on the grass. what can be done? i have searched in the internet and others have this problem too. this photo is from 10 seconds of the stopped mower. this brown spot will appear 2-4 days later.