Service And Maintenance - 2000 Hrs - Northern Lights M50C13 Operator's Manual

SP24. Checking and Adjusting Engine Valve Clearance
CAUTION
!
To prevent accidental starting of engine while performing
valve adjustments, always disconnect NEGATIVE (—)
battery terminal.
IMPORTANT: Valve clearance MUST BE checked and
adjusted with engine COLD.
1. Remove rocker arm cover and crankcase ventilator
tube.
IMPORTANT: Visually inspect contact surfaces of valve
tips, bridges and rocker arm wear pads. Check all parts for
excessive wear, breakage, or cracks. Replace parts that
show visible damage.
Rocker arms that exhibit excessive valve clearance should
be inspected more thoroughly to identify damaged parts.
2. Remove plastic plugs or cover plate from engine
timing/rotation hole (A, below) and timing pin hole
(B, below).
Flywheel housing timing holes - timing/rotation hole (A),
timing pin hole (B)
3. Using flywheel turning tool, rotate engine flywheel in
running direction (clockwise viewed from front) until
No. 1 (front) cylinder is at TDC compression stroke.
Insert Timing Pin in flywheel.
If No. 1 cylinder rocker arms are loose, the engine is at
No. 1 TDC compression.
If No. 1 cylinder rocker arms are not loose, rotate engine
one full revolution (360°) to No. 1 TDC compression.
Service and Maintenance - 2000 Hour
OM-C3 11/21
46
4. Adjust valves to specifications below using the valve
clearance adjustment procedure in the following blocks.
Loosen the jam nut 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
(below). Recheck clearance again after tightening jam
nut. Readjust clearance as necessary.
Specifications
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..................................... ........
5. Install rocker arm cover and crankcase ventilator tube.
6. Reconnect battery terminal.
27 N·m (20 lb-ft)