Cub Cadet MTD P71 Series - Manual (Page 20)

P71 Series Vertical Shaft Engines
14
6. Check valve lash between each valve stem and
rocker arm using a feeler gauge.
7. Intake valve lash (top valve) should be 0.004” -
0.006” (0.10 - 0.15 mm). See Figure 1.13.
8. Exhaust valve lash (bottom valve) should be 0.006”
- 0.008” (0.15 - 0.20 mm). See Figure 1.14.
9. Use a 3 mm hex key to loosen the jam set screw,
and a 14mm wrench to adjust the rocker arm ful-
crum nut. See Figure 1.14.
• Tighten the rocker arm fulcrum nut to close-up
the clearance between the end of the valve
stem and the contact point on the rocker arm.
• Loosen the rocker arm fulcrum nut to open-up
the clearance between the end of the valve
stem and the contact point on the rocker arm.
10. Hold the fulcrum nut with a 14mm wrench, tighten
the jam set screw to a torque of 80 - 106 in lbs (9 -
12 Nm) using a 10 mm wrench.
11. Double-check the clearance after tightening the jam nut, to confirm that it did not shift. Re-adjust if necessary.
12. Rotate the engine through several compression cycles:
• Observe the movement of the valve gear.
• Return the piston to TDC compression stroke and re-check the valve lash to confirm consistent movement
of the valve gear, including the slight bump to the exhaust valve from the automatic compression release.
13. Clean-up any oil around the valve cover opening, clean the valve cover, replace the valve cover gasket if nec-
essary.
14. Install the valve cover, tightening the valve cover screws to a torque of 62 - 80 in lbs (7 - 9 Nm).
IMPORTANT: Over tightening the valve cover will cause it to leak.
15. Install the spark plug.
16. Test run the engine before returning it to service.
Figure 1.13
0.005” feeler
gauge
Figure 1.14
0.007” feeler
gauge