MTD P90 series Shop Manual page 87

Remove all gasket material
Figure 8.6
6. Clean all of the gasket material off of the cylinder
head and the muffler. See Figure 8.6.
NOTE: The MTD engine uses a graphite exhaust gasket.
It is not reusable and must be replaced every time
the muffler nuts are loosened.
NOTE: The graphite exhaust gasket transfers heat from
the cylinder head to the muffler. The heat transfer
helps to keep the engine operating temperature
under control. Do not substitute an exhaust gasket
made from another material.
7. Install the muffler by following the previous steps in
reverse order.
NOTE: Tighten the manifold nuts to a torque of 22 - 26 ft-
lbs (30 - 35 Nm).
8. Test run the engine before returning to service.
Exhaust
81