Yes you can put premix down it. Then you have to pump it out, but at least it will dilute it with something volatile and oily. As a note, if you have a bunch in the mag side, you may want to pull the vacuum line off the carb and crank it. You may fine water puking out that line as well. I had a ton of oil in there and it actually pushed it up into the fuel pump diaphragm. So if you fuel pump stops working, look there.