Stihl FC 90 - Rocker Arms;Pushrods

34 Series 4180 Powerhead
Adjusting Valves
Valve clearance is adjusted with the
locknuts (1 and 2).
To increase valve clearance: Turn
nut counterclockwise
VA
249RA049
2
1
To reduce valve clearance: Turn nut
clockwise
– Turn engine over several times
and then check valve clearance
again.
Reassemble in the reverse
sequence.
– Thoroughly clean the sealing
faces on the cylinder and cover.
– Apply thin coating of sealant to
cylinder sealing face.
Follow maker's instructions.
– Tighten down cam gear cover
screws in crosswise pattern,
b 3.4
– Install new gasket for valve cover.
– Use new sealing ring for spline
socket head screw.
– Tighten down valve cover screw
firmly, b 3.4
– Tighten down nut on starter cup,
b 3.4
– Tighten down the spark plug,
b 3.4
– Remove the valve cover and cam
gear cover,
b 7.2
– Set piston to T.D.C.,
b 7.2
: Remove the locknut (1).
VA
249RA053
1
: Remove the sleeve (1).
VA
249RA054
1
: Remove the rocker arm.
VA
249RA055
: Take out the pushrod (1).
Reassemble in the reverse
sequence.
Make sure that the pushrod is
firmly seated in the rocker arm
and cam follower.
VA
249RA056
1
– Adjusting valves, b 7.2
7.3 Rocker Arms/Pushrods