Your speedster is a Jet Boat, not a PWC,(Personal Water Craft.) I'll post this thread in the Jet Boat section for you too. I recommend you run the same oil the previous owner ran if you know what that is. Here is some information from seadoo on the recommended oil and fuel;
Your model should use synthetic or synthetic blend.
Use High quality low ASH API TC Injector oil.
Do Not use NMMA TC-W, TC-W2 or TC-W3 outboard motor oils or other ash less type 2 cycle oil. Avoid mixing different brands of API TC oil as resulting chemical reaction could cause severe engine damage. Never mix Mineral or synthetics oil together.
Never use fuel containing more than 10 % alcohol,( Methanol or Ethanol) as severe damage will occur. The minimum of 87 octane is recommended for most engines.
What is the compression of the engine? It should be 150 psi. What has been serviced or rebuilt since it was new back in 1995? If it hasn't ever been serviced you have a lot of things to check out to be sure it is in good shape. It will be easier to give you advise if you can tell us what has been done in it's life. Things like the bearings should re greased on the jet pump shaft behind the engine, the jet pump oil should be changed yearly, all the electrical should be sprayed with silicone spray ad wd-40 All the nuts and bolts should be checked for tightness. The wear ring and impeller should be cheked for service use. The spark plugs should be good. Recomended spark plugs are NGK BR8ES gapped to.021"- .024". The battery should be checked and fully charged. If in doubt have it load tested at like Auto Zone for free. This is just a couple things to do and look over.
Karl
