Toro 159cc, Service Manual, Page: 28 / 46

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Valve Spring Free Length Specification
Standard Service Limit
1.2007” (30.5 mm) 1.1417” (29.0 mm)
NOTE: If this measurement is out of specification, complete engine
replacement is required. The only internal parts available for this engine are gaskets and seals.
Valve Seat Width Inspection
Remove carbon deposits from the combustion chamber. Inspect the valve
seats for pitting or other damage.
Valve Seat Width Specification:
Standard Service limit
0.0314” (0.8 mm) 0.0787” (2.0 mm)
Cylinder Head Warp Inspection
- Remove carbon deposits from the combustion
chamber.
- Clean off any gasket material from the
cylinder head surface.
- Check the spark plug hole and valve areas for cracks.
- Check the cylinder head for warpage with a straight
edge and a feeler gauge as shown.
Service Limit
0.00393” (0.10 mm)
NOTE: If this measurement is out of specification, complete engine replacement is required.
The only internal parts available for this engine are gaskets and seals.
STRAIGHT EDGE
FEELER GAUGE