The answer given is incorrect for the Suzuki DF6 (2007) outboard.
The motor has been examined and there is no access port in the
gear case. A new unit was also examined with the same result,
no access for flushing a running motor. Access as described was
found on a 9.9 HP and a 15 HP motor.
If I can figure out how to send this reply and accept the answer even
though incorrect, I will do so.