for my 2002 282, there is no switch or lever or anything required to change other than opening the waste deck fitting on the starboard side mid ship.
when the process is near done, i take my wash down hose into the head and fill the head/bowl and bunch of times to "flush" the tank as thorough as possible and re-start the pump out process until i can see that the waste water is near clear. This is a 2 man process. One guy in the head, one guy on the pump out hose. if you choose not to "extra rinse" your tank as i like to do, 1 person can do this job.
i'm assuming you're using a pump out station's hose/pump and accessing the hold tank via the starboard side deck fitting?
not really familiar with all variety of pump out stations exist, but the one i've used seems the norm and it has a hose with semi flexible tapered tip to that it will snuggly fit into the deck fitting hole and make a decent seal to better retain good suction. A very important step in using most pump out stations is that the hose needs to be "primed" to get it to work. You cannot simply stick the hose into the hole and press the button. there should be an approx 3" or better vertical pipe with open end with flowing water that you stick the hose tip into to help prime the hose. The hose should have a flow lever that you open to prime and once primed, you close and quickly insert into your waste deck hole, open the lever and the pump out process should begin. Most hoses have a "clear" section or window so you can see when the process is finished without risking premature pull out and "crap" spillage on your boat or in the water.
the pump out hose i've used does not "drop" or need to be "snaked" into the tank, it makes its' seal with the waste deck hole and the suction lifts the "crap" right out of the tank.
had to use the pump station a few times when my sub mac pump broke. much prefer to discharge offshore.
Hope this has helped. good luck.
