Generac 86640 - Manual (Page 31)

Timing Belt Inspection (Continued)
TOOTH BROKEN OR TOOTH ROOT CRACKED:
Caused by camshaft jamming,
distributor jamming, damaged
crankshaft or camshaft oil seal.
BACK SURFACE CRACKED OR WORN:
Caused by tensioner jamming,
overheated engine, interference with
belt cover.
SIDE SURFACE WORN:
Caused by Improper belt instal­
lation, defective crank pulley and/or
timing belt plate.
NOTE: Replace the timing belt If (a) side surface Is worn
to such an extent that cutoff performed during the man­
ufacturing process cannot be seen, (b) belt comers are
worn or rounded, or (c) belt fibers are frayed and coming
out.
BELT TEETH ARE WORN:
Caused by poor belt cover seal­
ing, coolant leakage at water pump,
defective camshaft, defective distrib­
utor, excessive belt tension. Some
problems that might be found under
Belt Teeth are Worn” include (a) can­
vas on tooth face worn, (b) canvas on
tooth is fluffy, (c) rubber layer worn or
faded white, or (d) weft worn or invis­
ible.
Timing Belt Installation
1. Check that No. 1 cylinder is at top dead center (TDC) of Its
compression stroke. Align the camshaft and crankshaft pulley
marks. See Figure 13.
2. See Figure 14. Install tensioner and return spring. Hook
the return spring to its stopper.
3. Slide the tensioner to the left and tighten the lock nut
temporarily (Figure 15).
4. Check that the water pump and tensioner pulleys can be
rotated smoothly and with no evidence of binding. Then,
install the timing belt.
CAUTION: The timing belt must be clean and free
of oil and water. Do NOT bend the belt. Arrow on
belt must point In normal direction of rotation.
Figure 14. Tensioner and Return Spring
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