Small Engine Troubleshooting Problems? Ask a Mechanic Now.
There are a lot of things that could cause it to shut off in 10 minutes - failing ignition system, failing fuel pump, oil pressure getting low, temperature getting high etc.
It all depends on which genset it is.
If the unit is only a year old, it is still under warranty.
The best thing to do is to get it to an Authorized Onan repair facility and have it repaired under warranty.
Working on the unit yourself can void your warranty.
If you don't care about losing your warranty, and buying your own parts, I can help with this. But I need to know which model it is. I can't even begin to help if I don't know which unit you have.