our XS-750 has the same problem. I can jumper the starter and it spins the motor at a very good speed but the engine and displays have no power. Battery tests show the battery is plenty strong. This beautiful pile of junk has only 19 hours on it. We bought this for my mother in law May2024 ( sadly, she passed away last month) and she did not register it for the warranty so I am stuck with whatever problem it has. It seems to be the Keyfob module since I can try different combinations of pressing the 3 buttons on the keyfob and the displays sometime come to life and it starts and runs fine until I shut it off and then it goes dormant again. I have read several stories where the keyfob module goes bad and HISUN even has a YouTube video on how to replace it. I hope to jumper across the Keybob module bypassing it and eliminate that defect in the design once and for all.