I have a 1990 X2 Jet Ski. There is a small plastic, threaded plug (looks like dip stick) on the engine cover plate. Does oil go in there? If so, what type of oil is it? Does this engine take oil other than 2 stroke? Right now I'm thinking that oil doesn't go in there and it's simply there to be able to look at the engine. I'm new at this. Thanks for any advice or help!

 

See 650 OIL CHANGE thread. Typically it is aluminum instead of plastic but serves the same purpose. No other oil other than 2 stroke is needed. You are correct sir
Rock