Originally Posted by Rv34
I do not know if it makes a difference but the generator was already working when my kid sa the extension cord on the pavement and decide to plug it in the wall. It took a good 15-20 seconds and the generator stopped
This should not have made a difference. I have a ONAN 5500 and have been plug into shore power and started my generator. I do not this on purpose, but by accident. With that said, I have never had a issue. It is my understanding the generator will always take priority over shore power. Something in the transfer box determines the load priority.
I still believe the timing is strange at best. You could have had something happen in the generator control circuit board. But, I would try all the other cheap ideas first. Nothing inside the transfer box is going to keep the generator from starting and running. I believe checking oil level, then move on to a checking fuel pump. The fuel pumps are really cheap to buy on Amazon. I carry one for a spare. I believe they cost somewhere between 18-25 dollars for a Onan 5500 model.
You could go to the files section in the forms and see if there is a troubleshooting guide for you model generator. Should also be lots of information on the internet. Good luck, let us know what you find wrong, it will help others.