Detroid Diesel S60 rpm

Hi,
I am a owner of a Detroid Diesel S60 engine. I use the engine in a test equipment.
The enginge runs from 1000 to 2100 rpm. The rpm can set up over a throttle.

How can I reduce the min rpm to 800 rpm?

Is it possible to set up the min rpm over J1587?

Thanks

Michael

Detroid Diesel S60 rpm