I put 2-cycle oil in a 4-cycle 5hp Briggs & Stratton outboard. Now it won't start. How do I fix this? (revised

Question

Oil is in a separate tank in engine cowl - gas & oil are not combined. Engine never ran with the bad oil - day 1 I filled oil tank, day 2 I tried to start engine. After I drain the oil tank, do I need to clean/flush the tank?

Answer 1

Your engine will be fine.  There is not a huge difference between 2 stroke and 4 stroke oil.  Even if you ran the engine with the 2 stroke oil, you would be fine.

Answer 2

no need to flush but soon after change the oil again and start fresh.

Answer 3

get new glasses than read oil container.

Answer 4

The not starting is a coincidence.  Drain the oil and fill with the right stuff - no need to flush the tank as the small amount that will be left will make little difference to the quality of the new (right)  oil.