Hello, my name is ***** ***** I am going to assist you with this.
Although the fuel pump is a distinct possibility, there are a couple other things it could be, also.
I can definitely help with this, as I have been an Onan technician for 15 years now.
But I need just a bit more information first.
1. While the engine is running, does it run smoothly, or is it running rough and surging?
2. When the engine shuts down, just it just shut off like someone turned it off, or does it start running very rough and then shut down?
3. When it shuts down, will it start right back up, or does it have to sit for a while before it will restart?