In article om,
wrote:

On Oct 8, 11:27 pm, wrote:
I own a Cessna 150 with a 150 HP engine installed (0-320- E2D)

The STC states the static RPM is not to be over 2250 RPM.

My airplane meets the Static RPM Requirement.

My question is am I getting the full 150 HP on takeoff??? turning
2250 RPM

A variable pitch prop (expensive) can keep constant RPM near the max
power output at takoff. But your fixed pitch prop is designed for
overall average operation. If it was pitched for near full power 2700
rpm at takeoff it would go beyond the max RPM at cruise and ruin the
engine.

The placarding probably relates to the STC, which "limits you to 100
hp", for certification purposes.

It is easier to get an STC for a higher power engine if you "limit, via
placards, the max power" to that called out in the original type
certificate.