If you think just about any TCW3 rated oil will work, then you should think of it like feeding yourself Top Ramen every day. Top Ramen is acceptable in a pinch, but it is definitely not for every day consumption.
As a good rule of thumb, you should spend at least $20/gal for oil. Don't be cheap and buy the $10/gal from the local mart! We like to run Maxima Marine Pro for our ski's and it runs about $38/gal. The reason cheap TCW3 rated oil isn't good is that yes its TCW3 rated, but that's more of a general rating.
There are two common ratings for PWC oil, TCW3 and API TC. The TCW3 rating is more specific to outboard engines and usually denotes a poorer grade oil as compared to an API TC rated oil. Outboard engines usually run about 6500 rpm's and don't have power valves unlike our modern PWC engines. API TC rated oils are considered an air cooled engine oil despite PWC engines being water cooled.
The reasoning behind using a different classification of oil is that its actually better oil. Air cooled engines take a pretty good beating due to expanding and contracting cylinders and pistons due to heat.
Oils are available as a non-synthetic, synthetic, or synthetic blend.
Now for the big Sea-Doo oil question. There is a lot of confusion on what kind of oil to put in a Sea-Doo. The reason Sea-Doo's require different oil is two fold:
- One, the 580, 650, 720, and 800 engines utilize a rotary valve instead of reed valve to regulate/time intake flow and need a low ash oil to be lubricated.
- Two, the Sea-Doo engines are more of a high performance engine and require a better oil.
Use the API TC rated oil in your Sea-Doo's and it's a good idea to get a synthetic or synthetic blend.
There is a great deal of discussion found online and we definitely recommend reading up on the specific requirements of your PWC. Any oil will work, but don't be cheap! Cheap oil will get you a shorter engine lifespan.