Oils....
For the most part, the general consensus in the forum is to use the Sea-Doo synthetic blend. If you don't have a dealer near or a pocket full of money, you can purchase the Synthetic blend of Quicksilver oil at your local Wal-Mart. Make sure you read the back label because not all Quicksilver oil is compatable with the Rotax engines requirements. It is written on the back label that you can use it in the Sea-doo.
The oil requirements is that it must be a Non NMMA, Non TCW3, low ash oil. Either mineral or synthetic........
Here's the sticky part. If you don't know what's in it now, you need to try and find out from the previous owner, or you'll have to remove all the oil from the engine (rotary chamber) before filling. You can not mix synthetic or mineral together.
I hope this answers your question.