;
The shaft mounted
4-MIX® engines
have a timing arrow on the flywheel that should
point at the ignition module mounting screw as a reference point when the piston
is at top dead center.
;
For the
4-MIX®
blower engine the “S” marked corner on the flywheel should be just
at the edge of the ignition armature leg when the piston is at top dead center.
Shaft Mounted Engine
Ignition Module Air Gap.
;
The specification for the ignition module to flywheel air gap is eight thousandths of
an inch for all
4-MIX® engines
.
;
The STIHL setting gauge can be used to check and properly adjust the air gap.
STIHL Part # 4118 890 6401.
Backpack Blower Engine
Backpack Blowers
4282 Series
Shafted Products
4180 Series
Valve Clearance
Break-in and normal wear tend to open up the valve clearance, and may lead to a loss of
power and performance.
;
The valve clearance for all
4-MIX® engines
is 0.1 mm. or four thousandths of an inch
when the engine is cold.
;
The instruction manual suggests checking the valve clearance around 135 hours of
operation.
;
A cylinder pressure leak down test will allow you to quickly determine the condition
of the valves and piston rings without disassembling the engine.
;
A special feeler gauge is required to check the minimum valve clearance. STIHL Part
# 4180 893 6400.
