I have an exmark Lazer Z with the kohler ch-730, 414 hours, it's a 2009 used for residential use only 1 to 2hrs a week question is does anyone know how hot the muffler should be running the tubes from head to muffler run around 300, but the muffler runs around 600, last summer it was missing and running extremely hot, my dealer found a blown intake gasket, thats the only problem in 14 years, thanks for any replies