We've had 3 Onan dealers give us opinions of why my generator would not carry a load. Columbus MO. came close and got it to charge batteries, but not the air conditioners. Cummins/Onan in Sacramento was able to get it right. They did a compression check and found 2 cylinders at 300 psi while the other one was at 206 psi. Should be at 400 all three. They wanted 9,500.00 to replace the Kubota and that price included the diagnosis. A new unit is over $9k plus labor and the diagnosis. Lots of 7.5 k used gens out there but didn't want to go that route. Found a new 8k for $8,500 plus shipping but we're still into Onan for diagnosis. Short story joined the Cummins Power Club for $20.00 and got 10% off parts and labor so out the door back to normal and new engine $8,500. SO what caused the engine's death? They found the air box where the filter is attached was cracked and basically dusted the engine over 1359 hours of running. There's no way one would know you had a crack in the air box. It is an all plastic box with blind nuts for attachment and the crack was at one of those nuts about 2" or so long. Oh yeah, got us a one year warrantee on it.