Generac Power Systems GTH760, Service Manual

Page: 36 / 76

SeCTIoN 5: CYlINder HeAd ANd vAlveS
5-4
4. Measure valve stem diameter at specified distance from
end of valve, as shown in Figure 5-11.
Replace if less than 6.9 mm (0.272 inches), or if total
clearance between valve stem and valve guide exceeds
0.12 mm (0.0047 in).
1.600” [40 mm]
Figure 5-11. Measure Valve Stem Diameter
5. Check valve springs for free length (Figure 5-12).
Replace if free length is less than 36.5 mm (1.437 inches).
Figure 5-12. Check Valve Springs
ASSeMble CYlINder HeAd
1. Install new valve stem seals.
a. Press seal on to intake valve guide bushing until it bottoms
(Figure 5-13).
b. Lubricate inner top lip of valve stem seal with oil.
Figure 5-13. Install Valve Stem Seals
2. Install valves (Figure 5-14).
Note: Lightly coat valve stems with oil or Spectra Lube
Red before installing valves. Be sure lubricant is not on
valve face, seat or end of valve stem.
EXHAUST VALVE
INTAKE VALVE
Figure 5-14. Install Valves
3. Place a shop rag or short section of rubber fuel line under
valves inside combustion chamber to hold valve in place
while compressing spring.
4. Install valve springs and valve spring retainers over
valve stems.
5. Compress valve spring and install keepers (Figure 5-15).