
Description
6.2 Liter (377 cid)
Margin after surfacing
Intake
0.79 mm (0.0311 in.) minimum
Valve Stem to Bore Clearance
1. Using a valve with a specified stem diameter or a new valve, measure valve stem clearance.
2. Attach a dial indicator to the cylinder head. Position it against the valve stem and close to the valve guide.
3. Holding the valve head off the seat about 0.158 cm (1/16 in.), move the valve stem side to side in the guide as shown.
Compare the stem clearance with the specifications.
32999
Measuring stem clearance
Description
6.2 Liter (377 cid)
Production
Intake
0.023–0.065 mm (0.0009–0.0025 in.)
Exhaust
0.033–0.075 mm (0.0012–0.00295 in.)
Service
Intake
0.025–0.094 mm (0.0010–0.0037 in.)
Exhaust
0.025–0.094 mm (0.0010–0.0037 in.)
4. If the clearance exceeds specifications on the exhaust valve and exhaust guide: it is necessary to replace the cylinder
head or install thin wall valve guide inserts.
5. If the clearance exceeds specifications on the intake valve and intake guide: it is necessary to install thin wall valve guide
inserts (Goodson, K‑Line) or replace the cylinder head. Intake valves are not available with oversize stems.
NOTE: The only engine machine shop reconditioning of the valve guides should be done with thin wall valve guide inserts
(Goodson, K‑Line, etc).
Valve Springs
1. Use a vernier caliper to measure the valve spring free length. This is for reference only, springs should be measured for
load at specified heights to determine if they are good.
20973
Description
6.2 Liter (377 cid)
Free length
53.39 mm (2.10 in.)
Engine Inspection and Assembly
Page 3B-46
© 2016 Mercury Marine
90-8M0099748 eng DECEMBER 2015
Summary of Contents for MERCRUISER
Page 2: ......
Page 6: ...90 8M0099748 eng DECEMBER 2015 2016 Mercury Marine Page iv...
Page 12: ...General Information Notes Page 1A 6 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 70: ...Maintenance Notes Page 1C 54 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 96: ...Troubleshooting Notes Page 1D 26 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 156: ...Installation Notes Page 2B 52 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 202: ...Engine Disassembly Notes Page 3A 46 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 286: ...Engine Troubleshooting Notes Page 3C 14 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 314: ...Waste Spark System Notes Page 4B 8 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 330: ...Charging System Notes Page 4C 16 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 404: ...MPI ECT Fuel System Notes Page 5A 34 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 424: ...All Models Notes Page 6A 20 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 448: ...Models with Closed Cooling Notes Page 6C 20 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 462: ...Water Flow Diagrams Notes Page 6D 14 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 474: ...Important Information Notes Page 7A 12 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 477: ...Manifolds and Elbows Notes 90 8M0099748 eng DECEMBER 2015 2016 Mercury Marine Page 7B 3...
Page 538: ...Compact Hydraulic Steering Notes Page 8B 12 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 558: ...Notes Color Diagrams Page 10A 2 2016 Mercury Marine 90 8M0099748 eng DECEMBER 2015...
Page 559: ...Notes Color Diagrams 90 8M0099748 eng DECEMBER 2015 2016 Mercury Marine Page 10A 3...
Page 565: ......