This a intermediate problem on Onan 7.5 dkdf. When press start button nothing happens at all but you can gently press down on left side control board all works. It then may work for days. It is Onan board 300-2604 , think it probably a bad board.
You might have a break in a soldered joint
If you can get at the board and remove it, I would carefully study all solder joints you can find to see is there are any cracks that might need re-soldering. Good luck.
jk
Got the board out but nothing jumps out as bad. All solder joints look ok. I still think board bad since very little pressure makes it work. I have ordered another board from flight systems. Will update after get new board next week.
Got the new board installed and all good now. Upon looking and at old board found a bad solder joint at the start screw on terminal strip. Tested and good. The wife still wanted new board since this was the second joint in 5 years. New board happy wife - happy life