I am a partner in a Cessna 182P with a O-470R engine.  After our last annual I noticed a change in our carb heat performance during run up. The reduction in RPMs is not as much and the increase in carb temperature is only 10 degrees.  I believe that the carb heat is not fully deploying.

When I ask the FBO if there are specs regarding (1) how much of a decrease in RPMs or manifold pressure or (2) in how much of a temperature increase should be obtained at full deployment I am met with a blank stare.  Are there any such specs?

Thank you