DLR 2007-02 New Special Tools ea 2012.doc
Page 4 of 9
STIHL Engine De-Carbonizer is a mild
chemical solution that breaks down ash
deposits formed by low ash 2-cycle engine oils
and is ideal for removing deposits from
exhaust valves on mix lubricated 4-cycle
engines and softens combustion deposits in 2-
cycle engines.
Procedure for using STIHL Engine De-
Carbonizer:
•
Move stop switch to the off position.
•
Remove spark plug.
•
Set piston to top dead center (on 4-stroke
engines: TDC between intake and exhaust
strokes at valve overlap with both valves
slightly open).
•
Completely fill the combustion chamber
with STIHL Engine De-Carbonizer through
the spark plug opening and let stand for
approximately one hour. Do not leave the
liquid in the cylinder any longer than 12
hours. Note that the de-carbonizer fluid
works best and only needs to soak for
approximately 15 minutes if the engine can
be started and warmed up before applying
the chemical.
•
Pour the de-carbonizer fluid out of the
spark plug opening onto an absorbent
towel. The solution can be disposed of in
normal trash collection and is not an
environmental hazard.
•
Pull the starter rope several times to clear
the cylinder. On 4-cycle engines, ensure
that the valve clearance is set properly.
•
Install the spark plug and start the engine.
•
Note: the muffler spark arrestor screen
may need to be cleaned of loosened
combustion deposits after running the
engine.
In the event the de-carbonizer fluid does not
correct the problem, the engine will have to be
disassembled for further inspection and repair.
The tool kit also includes some specialized
tools including a 10 mm piston stop (part no.
4282 890 2700) designed for use with all
STIHL 4- Stroke engines. The piston stop is
used to block the crankshaft from rotating
when performing repairs.
Rotate the crankshaft until the piston
reaches BDC (bottom dead center). Thread
the piston stop into the spark plug hole until
fully seated.
Before the removal or installation of any
components, rotate the crankshaft in the
direction of the item to be removed or
installed until the piston contacts the stop.
Use the proper tools to remove or install the
desired part.
Important note:
Do not use an
air or electric
powered impact wrench to assemble or
disassemble components on any STIHL
product. Doing so will shear the flywheel key
and damage other components such as
clutches and crankshafts.
