Re: 2003 yamaha 4 stroke 9.9
the 2 strokes can be damaged by it , but the 4 strokes do not get the lube from from the fuel, so they should be OK.
I would have it fixed, something is not right. Choke or prime start is not functioning correctly.
old fuel does not burn as well as fresh and carbs need to be serviced from time to time.