Chain Lubrication - Stihl MS 661 Manual

3.3

Chain Lubrication

In the event of trouble with the
chain lubrication system, check and
rectify other sources of faults
before disassembling the oil pump.
Condition
Chain receives no oil
Machine losing chain oil
Oil pump delivers insufficient oil
10
Cause
Oil inlet hole in guide bar is blocked Clean oil inlet hole
Intake hose or pickup body clogged
or intake hose ruptured
Valve in oil tank blocked
Teeth on worm worn
Oil pump damaged or worn
Oil pump damaged or worn
Oil suction hose connection
damaged
Gasket between two halves of
crankcase faulty or crankcase
cracked
Oil pump damaged or worn
Oil pump delivery rate set too low
Worm driver is loose
Sealing ring between oil pump and
crankcase damaged
.
Remedy
Fit new intake hose and pickup
body
Clean or replace valve
Install new worm
Install new oil pump
Install new oil pump
Install new oil suction hose
Install new gasket, inspect both
halves of crankcase and replace if
necessary
Install new oil pump
Adjust oil pump
Install new worm
Replace the sealing ring
MS 661, MS 661 C-M