Testing Compression Pressure; Installing New Oil Seals At Starter Side; Installing New Oil Seals At Flywheel Side - Stihl 4180 Series Service Manual

If air is escaping at the cylinder inlet/exhaust ports or
around the pushrods, the cause may be:
Carbon deposits on inlet/exhaust valve
–
Worn piston rings
–
Seized piston
–
16.4

Testing Compression Pressure

Interactive video "Testing Compression
Pressure"
Remove the cover, @ 4.3.
N
Pull boot (14) off the spark plug.
N
Unscrew the spark plug (13).
N
Screw the compression tester 5910 850 2000 (25)
N
into the spark plug hole.
Pull rewind starter firmly and quickly several times.
N
Read compression pressure on pressure gauge.
N
Specification: 6 – 7 bar
If compression pressure is less than6 bar, check valve
clearance, @ 15.3.
If valve clearance is correct, check cylinder, piston and
piston rings for scores and damage.
16.5

Installing New Oil Seals at Starter Side

Remove the shroud, @ 4.2.
N
Remove the rewind starter, @ 5.2.
N
25
Fit the locking screw 4282 890 2700 (25).
N
44
Turn the crankshaft counterclockwise until the piston
N
butts against the locking screw.
Unscrew the nut (3) and remove the starter cup (4).
N
Apply puller 5910 890 4400 (1) with No. 3.1 jaws to
N
oil seal (5) and clamp the arms.
Pull out the oil seal (5).
N
Push the installing sleeve 4112 893 2400 onto the
N
crankshaft.
32
5
Lubricate lips of oil seal (5) with multipurpose grease.
N
Push on the oil seal (5) with its open side facing the
N
crankcase.
Use press sleeve 1115 893 4600 (32) to install the oil
N
seal (5).
16.6

Installing New Oil Seals at Flywheel Side

Remove the shroud, @ 4.2.
N
Remove the fan housing, @ 7.1.
N
30
31
Series 4180 Powerhead