Self FixerCom.DE

Valve clearance adjustmentYamaha Marine Outboards F4A/F4

1. Remove:
   • Top cowling
   • Bolt (carrying handle)
   • Carrying handle 2 (protector)
   • Bottom cowling 2
   • Bolt (recoil starter)
   • Recoil starter ass'y
   • Spark plug
2. Remove:
   • Bolt (cylinder head cover) "1"
   • Cylinder head cover "2"
   • Gasket (cylinder head cover)
   
3. Position:
   • Flywheel rotor
   NOTE:
   Turn the flywheel rotor ass'y clockwise and check that the valves are fully closed with there rocker arm in free position, and set the magnet "3" on the flywheel rotor with both core ends "4" of the ignitor ass'y "5" mated as shown.
   
4. Inspect:
   • Valve clearance
     Use feeler gauge.
     Out of specification - Adjust.
   Valve clearance
   

   Intake "A":	0.10 0.02mm (0.004 0.0008 in)
   Exhaust "B":	0.10 0.02mm (0.004 0.0008 in)

   • Loosen:
     • lock nut (rocker arm)
     
     
   NOTE:
   When loosening the locknut "6", lock the adjuster "7", otherwise the locknut "6" will not loose.
   • Adjust:
     • Intake valve clearance
     • Exhaust valve clearance
     
   Adjustment steps:
   • Loosen the lock nut and insert the 0.10 mm (0.004 in) feeler gauge between rocker arm and valve stem.
   • Turn adjuster 7 to obtain the proper clearance.
   ---
   Turning in "C" - Valve clearance decreases.
   Turning out "D" - Valve clearance increases.
   • Tighten:
     • locknut "6"
   
   Locknut (rocker arm):
   10 Nm (1.0 m/kg, 7.2 ft/lb)
   NOTE:
   Tighten the locknut, keeping the adjuster fixed.
   • Install:
     • Gasket (cylinder head cover)
     • Cylinder head cover
   Cylinder head cover:
   11 Nm (1.1 m/kg, 8.0 ft/lb)
   • Install:
     • Spark plug

   Updated on: Sunday, November 22, 2020