MTD P90 series Shop Manual page 94

P90 Series Vertical Shaft Engines
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.
88
Figure 9.11
Seat angle is 45
Seat
contact
Figure 9.12
Inspect for a
burnt edge
Figure 9.13
Seal
0.028 - 0.035"
o
margin
o
45