Hi - My Onan 8K genset developed a problem on 9/6/2014. It starts fine, runs for about 5 seconds then dies. If you're having troubles I documented what I did to diagnose the problem.
My genset is: Onan 8K Quiet Diesel (circa 2005)
The genset displays diagnostic codes presented as a two level blink code system. The light in the start/stop switch is the readout. After its electronics detects a fault, it blinks a first level code of 1,2 or 3 blinks. First level codes of 1 and 3 have a second level blink code associated with them. Briefly pressing the STOP switch will cause the second level blink codes to appear. There's a tens digit of 1-4 and a ones digit from 1-9. A brief pause exists between the digits. The tens digit blinks out first followed by a pause then the ones digit blinks last. This sequence repeats for 5 minutes so you have plenty of chances to count the blinks and construct a 2 digit fault code.
All the fault codes and how they work are documented in the service manual. You can view that HERE
. Go to page 21 TROUBLESHOOTING.
In my case I got a fault code of 27 which is "PMA sense lost." or "Unable to sense PMA frequency."
One other point about the generator is it isn't a cheaper version for RV service. The Onan generator rates this unit for RV/Commercial service. The commercial version includes a different battery charging system and hydraulic pump. Some also have a PTO. This is used for bucket trucks and other commercial applications. Otherwise the two generators (RV/commercial) contain exactly the same parts.