Adjustments; Valve Clearance - Toro Groundsmaster 300 Series Service Manual

Adjustments

Valve Clearance (Fig. 10, 11, 12)
Check the valve clearance after the first 50 hours of
operation and every 400 hours of operation after that.
1. The engine must be cold when the valve clearance is
checked.
2. Remove the air breather hose from the rocker cover.
3. Remove the rocker cover nuts and washers. Remove
the rocker cover.
4. Tighten the cylinder head bolts to the proper torque.
The rocker assembly must be removed before tighten-
ing the cylinder head bolts. When tightening the cylinder
head bolts, lower the coolant level in the engine, loosen
the bolts slightly and then re-tighten in the sequence
shown.
M12 bolt torque (wet): 1.5 - 12.5 kgm (83 - 90 ft-lb)
M10 bolt torque (wet): 6.5 - 8.0 kgm (47-58 ft-lb)
Rocker stay bolt torque: 1.5 - 2.2 KgM (11 - 16 ft-lb)
5. Rotate the crankshaft until the TDC mark (located
next to the injection timing mark(s) on the pulley lines
up with the registration mark on the gear case. This will
be TDC on cylinder No. 1.
NOTE: There are two TDC positions (compression and
intake strokes). At compression TDC the rocker arms
will not move when the crankshaft pulley is rotated a
small distance each way. Compression TDC is where
the valves are to be adjusted.
6. Measure the valve clearance by using a thickness
gauge inserted between the valve stem and rocker arm.
The correct valve clearance for both the intake and
exhaust valves is 0.25 mm (0.01 in.).
7. To adjust the valve clearance, loosen the adjusting
lock nut and turn the rocker arm adjusting screw clock-
wise or counterclockwise until you get the correct clear-
ance. Tighten the locknut securely. Check to make sure
that the clearance was not changed while tightening the
locknut.
8. Perform steps 6 and 7 of this procedure for cylinder
No. 2 and 3 while at their TDC position. Turn the
o
crankshaft 240 clockwise to get No. 3 cylinder TDC.
Turn the crankshaft an additional 240
No. 2 cylinder TDC.
9. Install the rocker cover. Install the rocker cover nuts
and washers. Install the air breather hose on the rocker
cover.
®
Groundsmaster 300 Series
o
clockwise to get
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Figure 10
Figure 11
Figure 12
Adjustments