Stihl 4-MIX Troubleshooting And Repair Instructions Download

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If the engine is being assembled and the flywheel is not in place yet, just be sure the

piston is at top dead center to time the cam correctly.

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To install the cam on the backpack blower engines, notice that when the piston is at

top dead center, the cam lobe is pointing up when the alignment marks are
matched up. Now install the dowel pin.

Rotate the crankshaft until the tip (arrow) of the
flywheel lines up with the ignition module as
shown.

Fit the cam gear so that the arrows (2) and (3) are
in alignment with the notches (1and 4) in the
cylinder.

Summary of Contents for 4-MIX

Page 1: ...spark the spark plug the ignition module or stop switch system is at fault If the fuel system is completely restricted the engine may not fire at all when trying to start it Squirt some choke spray in...

Page 2: ...e that the throttle returns to idle easily and smoothly On a shaft mounted 4 MIX product inspect the cable for fraying where it slides over the plastic cam on the carburetor flange Example B B A 4180...

Page 3: ...s achieved Ignition Module Check for spark with a spark tester that loads the ignition module Modules can have intermittent faults Heat related failures where the spark returns after the module cools...

Page 4: ...d at least once a year or more often if needed The air filter element used on the 4 MIX shaft mounted engines should never be cleaned in solvent Brush off any loose debris and clean it with compressed...

Page 5: ...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...

Page 6: ...is less than 10 the sealing of the combustion chamber is acceptable If leakage is over 10 you will need to identify the area of leakage and repair the leak Listen at the muffler carburetor flange inle...

Page 7: ...holds pressure then apply a vacuum of negative 0 5 bar or about negative 7 pounds per square inch The vacuum reading should not leak to above negative 0 3 bar or about negative 4 pounds per square in...

Page 8: ...r visually Before testing or disassembly visually inspect the carburetor for damage If something on the carburetor is physically broken or worn most likely the carburetor will need replacing and no fu...

Page 9: ...ge should drop Continue until the gauge reading indicates a slight vacuum This will pull a vacuum on the metering chamber The gauge reading should indicate a vacuum and hold steady for at least one fu...

Page 10: ...ing when hot poor acceleration or loss of power when hot Special Service Procedures Special Tool Application 10mm Piston Stop Flywheel Removal To remove the flywheel or starter cup nut on a 4 MIX engi...

Page 11: ...use an impact wrench on any STIHL product Engine De Carbonizing Procedure If a 4 MIX engine is showing more than 10 leakage past the exhaust valve the most likely cause is carbon build up on the valve...

Page 12: ...backpack blower engines notice that when the piston is at top dead center the cam lobe is pointing up when the alignment marks are matched up Now install the dowel pin Rotate the crankshaft until the...