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download Service Letters pdfs
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A-1 Exhaust Valve Retainer Washer P/N

A-2 Ball Bearing Crankshaft Thrust P/N B-550

A-3 Excessive Cylinder Wear

A-4 Valve Springs

A-5 Relocation of all Propellers in the Hubs

A-6 Valve Spring P/N 7741

A-7 Service Memorandum to Owners of Airplanes Powered by Warner Super-Scarab 145 HP Engines

A-8 Valve Springs

A-9 Replacement of Link Rod Bolts

A-10 Replacement of Exhaust Valve Springs

A-11 Periodic Inspection of Crankshafts on
125 HP Engines

A-12 Valve-Carburetor Heat Control Assembly No. 8290 - Modification of Linkage

A-13 Pistons, Exhaust Valve, Cylinder, Link Rod

A-14 Spark Plugs-Installation, Inspection, Maintenance, and Overhaul

A-15 Cylinder Attaching Studs - Proper Maintenance, Inspection, and Assembly Procedure

A-16 Carburetor Heat Control Valve Assembly No. 7720 and 7989 - Drilling of Drain Hole
to Eliminate Fire Hazards

A-17 Replacement of Cylinder Hold-Down Stud, Gasket between Cylinder Barrel and Crankcase

A-18 Recognition of Reinforced Taper Crankshaft
and Availability of New Heavier Stem Exhaust Valve

M-10 Valve Springs for New Engines

AD 51-04-02 Cylinder Holddown Studs
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