Service Instruction No. 1257 G

Horsepower, Manifold Pressure and RPM Values

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Supersedes Service Instruction No. 1257F

May 16, 2008 


Lycoming supercharged and turbocharged aircraft engines.


During engine maintenance.

It is important to note that all Lycoming supercharged (GSO and IGSO) engines attain take­off power at  less than full throttle, while some turbocharged engines attain take­off power only at full throttle and others  at part throttle. It is the operator’s responsibility to know the type being operated.

Get It Exchanged

Use our Engine Exchange Program to order a new, rebuilt, or overhauled engine to experience more airtime and less downtime.