Exmark METRO Operator's Manual page 36

c) Belt must be tight enough to not slip during heavy loads while cutting grass.
Overtensioning will reduce belt and spindle bearing life. To adjust belt
tension, loosen the 5/16" whizlock nut on turnbuckle and rotate the
turnbuckle; rotate turnbuckle toward rear of mower to tighten, and toward
front of mower to loosen belt tension (See Figure 21). Leave a minimum of
5/16" (.79 cm) of the eyebolt threads engaged on both ends of the turnbuckle.
For 48" Decks: If there is no adjustment left in the turnbuckle and the belt is
still loose, the rear idler pulley can be repositioned in the front hole (See Figure
21). The belt guide located next to the pulley must also be repositioned in the
front hole when the pulley is moved. The turnbuckle will need to be readjusted.
Check belt tension after the first hour of operation and at least twice during the
first 24 hours of operation. Adjust as necessary.
d) Proper belt tension will require about 10 lbs. side pull on belt, halfway between
pulleys (See Figure 21, Point A) to deflect belt 1/2" (12 mm).
e) Check belt guide under the engine deck to see that it is properly set. (See
Section 5.2.7). Also check the blade brake adjustment. (See Section 5.2.6)
5.2.6 Blade Brake Adjustment:
a) Stop engine and wait for all moving parts to stop. Remove key or spark plug
wire(s).
b) Disengage blades.
c) Make sure the blade brake pad rests against the sheave. Adjust the spring
mounting bolts to properly align the pad on the sheave. See Figure 22.
d) Check the distance between the spacer and the nut at the end of the blade brake
rod. The distance should be between 1/8" and 3/16" (3 – 5 mm). See figure 22.
e) Engage the blade control and check to make sure the blade brake pad clears
the sheave.
FIGURE 21
MOWER DECK BELT ADJUSTMENT
FIGURE 22
BLADE BRAKE ADJUSTMENT
- 31 -
48" Deck Shown
for Reference Only
(3-5 mm)