12.3.1 Adjusting Uprated; Valve - Stihl MS 661 Manual

12.3.1 Adjusting Uprated

Oil Pumps
See owner's manual for most
suitable settings for different uses.
When oil pumps with an increased
oil flow rate are set within range "a",
note that the oil tank may run dry
before the fuel tank and the saw
chain may then have insufficient
lubrication.
Therefore, if pump is set to range
"a", fill fuel tank to half full mark only
or refill oil tank when fuel tank is half
empty.
1
An oil pump with an increased oil
flow rate can be identified by the
limit stop pin (1).
If the limit stop pin (1) is driven fully
home (recessed in the housing), the
adjusting screw can be set to
maximum oil flow.
96
12.4

Valve

A valve is installed in the housing
wall to keep internal tank pressure
equal to atmospheric pressure. The
valve must be replaced if it is faulty.
– Open the oil tank cap and drain
the oil tank b 1.1.
: Use a 6 mm drift to carefully
drive the valve out of its seat in
the housing and into the oil tank.
– Remove the old valve from the oil
tank.
Installing
Check correct installed position.
: Insert the valve in the crankcase
bore (arrow).
– Use a 6 mm drift to carefully
drive in the new valve from
outside – note installed depth.
: Drive the new valve into the bore
to a depth of 1 +/- 0.2 mm (a).
– Reassemble all other parts in the
reverse sequence.
MS 661, MS 661 C-M