John Deere 6068 Lawn Mower User Manual


 
Lubrication & Maint./2000 Hour/24 Month
OUO1089,0000208 –19–27JUL06–2/5
4. With engine lock-pinned at TDC of No. 1 piston’s
compression stroke, check valve clearance to following
specifications. (Use sequence for 4-cylinder or
6-cylinder engines as outlined on next page.)
Specification
Intake Valve Clearance Checking
(Rocker Arm-to-Bridge) (Engine
Cold)—Clearance 0.31—0.38 mm (0.012—0.015 in.)................................
Exhaust Valve Clearance
Checking (Rocker Arm-to-Bridge)
(Engine Cold)—Clearance 0.41—0.48 mm (0.016—0.019 in.)...................
OUO1089,0000208 –19–27JUL06–3/5
RG12169 –UN–03JUL02
Adjusting Valves
A—Adjusting Screw Jam Nut
5. If valves need adjusting, use the appropriate valve
clearance adjustment procedure on the next page and
adjust to specifications below. Loosen the jam nut (A)
on rocker arm adjusting screw. Turn adjusting screw
until feeler gauge slips with a slight drag. Hold the
adjusting screw from turning with screwdriver and
tighten jam nut to specifications. Recheck clearance
again after tightening jam nut. Readjust clearance as
necessary.
Specification
Intake Valve Clearance
Adjustment (Rocker
Arm-to-Bridge) (Engine Cold)—
Clearance 0.36 mm (0.014 in.)...................................................................
Exhaust Valve Clearance
Adjustment (Rocker
Arm-to-Bridge) (Engine Cold)—
Clearance 0.46 mm (0.018 in.)...................................................................
Rocker Arm Adjusting Screw Jam
Nut—Torque 27 N•m (20 lb-ft)....................................................................
NOTE: While rocker arm cover is removed, test glow
plugs. (See following procedure.)
6. Install rocker arm cover and crankcase ventilator tube.
7. Reconnect battery terminal.
35-13
080706
PN=171
Continued on next page