Onan KY Series, fault code 13
My Onan 4000 gas genset shut died after running for several hours last Sun. Restrated it and as soon as the roof A/C came on it died again. Shows fault code 13 (undervoltage - reduce electrical load on genset). Started trying to troubleshoot it today and came up with the following -
Oil level good, spark plug good, air filter clean, fuel tank full. Genset will start easily and run indefinitely as long as there is no load on it. Voltmeter shows 121.8 volts at outlet. As soon as I add a load (15k BTU roof air) I hear rapid clicking coming from my transfer switch and the genset dies, showing fault code 13. House batteries test good on multimeter and show 13.2 volts when disconnected from shore power. Chassis battery tests good, but shows just 12.5 volts.
Any thoughts? Slip ring need cleaning? Chassis battery getting weak, near end of life? Transfer switch gone bad? Control board on genset?
Any help greatly appreciated.
2013 Thor A.C.E. 29.2
SeaDoo Speedster 150 HO or 2015 Chevy Colorado Z71 toad, depending on season.