This used generator was professionally installed at my home. The previouus owner upgraded to a much larger unit and was serviced yearly with 200 hours on it. I know the previous owner and of the reliability in previous location. Major service performed 3 months ago. Current install is without transfer switch. Understand gas pressure(s) must be present and maintained for unit to start and to remain on. Electrical to panel installed. Breakers on unit and to house off. Oil full, battery charged and tested with load. Fuses under run, auto, off toggle have been tested and are good. When toggle placed in run position, unit makes no attempt to start. Gas installers say its electrical, electrical installers says its a fuel prob. Kohler service wants $500 for expert tech to visit and diagnose. Not opposed, just looking for ideas first.Thanks in advance.

Electrical Supplies - Kohler - 12 kW Emergency Power System - 12RES-L