Hobart 60CU20 Operation And Maintenance Manual With Illustrated Parts List page 206

OM-2226 / Operation and Maintenance Manual
60CU20 / Series 500062 / 400 Hz. Generator Set
4) Operation with:
a) Improper fuel, lubricants or coolant.
b) Parts or elements unauthorized by the manufacturer.
c) Unauthorized modifications.
5) Operation in poorly ventilated areas.
May 2, 2013 Appendix A
Page 6