Specifications

78
8. Mount the cylinder cover or flange with the
governor gear assembly installed to the
crankcase using dowel pins to position the
cover and a new gasket. Install the cover
down onto the crankcase and slightly rotate
the crankshaft to allow the governor gear to
mesh. Do not force. Apply a drop of blue
Loctite 242 to the cover screw threads and
tighten to the specified torque.
On engines with ball bearings in the cover,
install a thrust washer (if applicable) over the
crankshaft, followed by the retaining ring.
On OHV 13.5 -17 engines, install the oil pump
drive shaft into the slot in the end of the
camshaft. Apply engine oil and install the oil
pump ring and rotor, followed by a new "O"
ring and the pump cover. Tighten the screws
to 50-70 inch pounds (5.5 - 8 Nm) torque.
9. Install the breather assembly.
10. Rotate the crankshaft to place the piston at
Top Dead Center (TDC) on the compression
stroke.
NOTE: Always cut the valve seats, never only
lap the seats.
11. Pre-assemble the valves and spring
assemblies into the cylinder head on all
engine models EXCEPT OHM, OHSK80-130,
OVM, OVXL (diag. 65 on page 79). Use a
small block to support the valves tight to their
seats while placing the head on a flat surface.
For models OHH and OVRM, install the
springs (dampening coils toward the head)
and retainers on the valves and use fingers
to compress the springs until the notch in the
retainer is located in the notch in the valve
stem. Repeat the procedure for other valve.
For OHV models, place the springs
(dampening coils toward the head) over the
valve guide and place the valve caps on the
springs with the larger opening away from the
springs. Use spring compressor tool part #
670315A installed on a rocker arm stud, and
either turn the stud in or secure with a locking
nut as shown so about 1-1/2" (38.1 mm) of
the stud is exposed. Compress the spring and
install the valve retainers to lock the valve to
the valve cap. Repeat the procedure for other
valve.
RETAINERS HELD BY SPRING
TENSION AGAINST THE CAP
CAP
RETAINER
ROTOR
SHAFT
NOTE: INSTALL OIL PUMP AFTER THE SUMP IS ON
60
61
62
VALVE SPRING
COMPRESSOR TOOL
PART NO. 670315
63
ROTARY PUMP
RING
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