help with mower identification.

[Phototone]

my brick is a '77 and the other is an '87 with a beat to **** deck. brick is probably running 50 lbs. compresion cut with it last night and MAN THAT THING IS LOUD AS HELL. is it normal for a magnesium deck to vibrate at the resonant frequency or is it something else?

ill post a vid of the brick running after school if you guys wanna see how it sounds to help diagnose the problem.:smile:
Oh i almost forgot i think my bricktop is running the same speed as my duraforce which doesn't seem right. ill post the vid around 4-5pm

A bricktop Lawnboy has a cast aluminum muffler under the deck, and is generally much quieter than a later model Lawnboy with a steel muffler. There is a seal between the exhaust port on the cylinder and the muffler plate (the deck the engine block is bolted to). The seal is a flexible "rubber" gasket with a metal sleeve that fits over it. When you bolt the block down, it compresses and seals. It could also be that you are either missing the bottom bolt-on part of the cast muffler, or that the screws are loose and not holding it together sealing it. The muffler is under the deck, between the deck and the blade.