Yamaha 650 JetSki smoking... forgot to add oil. Whoops! HELP! :)?

[Kelly Belle]

Hi! I bought a 1990 Yamaha 650 Waverunner, filled it up w gas like my SeaDoo and didn't realize that the Yamaha need 2 cycle oil mixed in w the gas. So. I put it in the water, it started ran really slow and smokes. I realized the problem and put as much oil as we had straight into the gas tank and shook the waverunner in the water. It was about 12 ounces for 6 gallons of gas which is about 4 ounces short I believe. Still smoked and ran slow. I've since gotten it out and not started it, but I'm sure i would still start so I didn't kill it just yet. It maybe ran for 30 minutes? Any ideas of how I should proceed? Help please! I'm obviously a beginner when it comes to jetskis. Thanks for any help!