How does one "derate" an engine?

[SVSUSteve]

Just out of curiosity but I came across a mention on another website of an engine that had been "derated" from a higher HP to a lower. How exactly does one do that? Could it be as simple as limiting throttle travel or would more complex measures be necessary to do this safely? Given my status as "definitely not an engine guy", I figured I would put this question to those who are.

Thanks in advance.

 

[Head in the clouds]

 

[SVSUSteve]

 

[BBerson]

 

[Head in the clouds]

 

[SVSUSteve]

 

[Head in the clouds]

 

[cluttonfred]

 

[Toobuilder]

 

[Toobuilder]

 

[Lemans]

 

[clanon]

 

[BBerson]

 

[clanon]

 

[Toobuilder]

 

[Lemans]

 

[SVSUSteve]

 

[clanon]

 

[Dan Thomas]

 

[Pops]