912 ULS-FR

Hi everybody.

How comes that the 912 USL-FR (Blue valves cover) are derated at 90 hp @5500 RPM ?

What are the differences with a regular 912 ULS ?

Where may I find the proper operator manual with its performances ?

Is it possible to retrofit them when overhaul, if yes, what should be done ?

Mine is S/N 4430049.

Thanks for reading and helping.

Patrick