Cub Cadet MTD P90 Series - Manual (Page 94)

P90 Series Vertical Shaft Engines
88
5. Lift the springs off of the valve stems.
6. Slide the valves out of the cylinder head.
NOTE: Only the intake valve has a valve guide seal.
See Figure 9.11.
7. Inspect the valve seat. See Figure 9.12.
• Valve seats are 45 degrees, with a 25 degree
topping cut and a 60 degree narrowing cut.
• Seat width should be 0.028” - 0.035” (0.7 -
0.9mm) with a margin of 0.049” - 0.061 (1.25 -
1.55 mm) on the exhaust valve and 0.027”
(1mm) on the intake valve.
NOTE: The valve seat can be ground to clean it up
as long as the finished seat is within the tol-
erances listed above.
8. Inspect the valve stem. See Figure 9.13.
9. Inspect the valve springs.
NOTE: Valve spring free length should be at least
1.2” (30.5mm). Original length is 1.54”
(39mm).
10. Install the valves in the cylinder head by following
steps 2 - 5 in reverse order.
Figure 9.11
Seal
Figure 9.12
Seat angle is 45
o
0.028 - 0.035”
Seat
contact
margin
Figure 9.13
45
o
Inspect for a
burnt edge