You already know the most important fact about oil: Without it, your personal watercraft's engine will transform itself into a very large and expensive paperweight in a fraction of a second. You don't get a choice as to using it or not.
Choices abound, however, when it comes to selecting a particular kind of oil. In fact, figuring out what you need can be a slippery problem. That's why we consulted technical manuals and talked to a couple of experts in the field for some slick technical advice. Here are the answers to some basic questions.
Is it animal, mineral or vegetable?
Oil can be derived from a number of sources in nature, including animals - but we don't know of any watercraft engines which use whale or cod liver oil as a lubricant. Most motor oils are mineral or vegetable in origin.
Mineral-based oil is derived from petroleum (crude oil, that is - black gold, Texas tea) through fractional distillation, a process briefly explained in the article On the gas," April '97. Other oils are extracted from vegetable matter. While you won't get very far pouring Mazola into your PWC, the seeds of the castor-oil plant yield a suitable base for motor oil. Oil can also be produced from other substances through chemical processes, in which case it is referred to as synthetic. Vegetable and synthetic oils are chemically very different from petroleum-derived oil and should not be mixed with it.
So what exactly is in that little bottle?
Harold Tucker, lubricants technical director for Phillips Petroleum, rattles off statements like, Oil may be a mixture of clean-burning light solvent neutrals and bright stocks which protect against piston-skirt scuffing" as easily as some of the rest of us say, May I have some fries with that burger?" He goes on to say that bright stocks don't burn cleanly, and so are replaced in some oils by synthetic polymers which have similar anti scuff properties but don't leave residue when burned. Oil may also contain ash less dispersants, which help to prevent deposits and keep piston rings free.
What's different about two-stroke oil?
When a car burns oil, it's usually considered a bad thing. When a personal watercraft burns oil, it's just business as usual. While four-stroke engines use oil over and over again until its changed every 3000 miles (yeah, right), the oil in a two-stroke engine must be mixed with the gasoline to lubricate internal parts, and is therefore consumed in the combustion process. That's why it's so important that two-stroke oil be designed to burn more cleanly than four-stroke oil. An oil which didn't burn cleanly could leave deposits in your engine which could result in significant withdrawals from your bank as you struggle to pay the repair bills.
What does TC-W3 mean?
Oils carrying the designation TC-W3 have been certified by the National Marine Manufacturers Association. TC means two-cycle (two-stroke). W means the oil is appropriate for water-cooled engines such as those found on personal watercraft and outboard boats. The 3 on the label means that it is a third-generation oil. The TC-W3 certification replaced the earlier designations TC-W and TC-WII, and indicates that the oil has passed additional testing procedures designed to exclude inferior oils. Oil which does not display this symbol may not have undergone these procedures or may have failed one or more tests.
How much difference is there among brands?
Any brand of oil should work in your engine as long as it meets the requirements for water-cooled two-stroke engines. However please check your owners manual for your specific vehicle.
"We all have different formulations, but I'm not aware of any oil that's poor quality," Lechien says. "There's good product out there and there's better product. It falls on the consumer to make a decision." Factors to consider include past experience and friends' recommendations, but keep in mind that problems blamed on oil are often due to improper maintenance and operation. Also, labels such as "high-performance" or "race oil" have no legal definition. You may want to ask a technical service representative to explain what's behind these claims.
Do I have to stick to a certain brand to keep my warranty in force?
Your owner's manual may recommend that you use the manufacturer's brand of oil, but it doesn't require you to do so. Although dealers may try to sell you a specific brand of oil, they cannot require you to use it. In fact, anyone who says you must use their oil to keep your warranty in force is violating federal law, unless they can prove to the Federal Trade Commission that no other brand of oil will work (which they can't) or they supply you with the oil for free (which they won't). As long as you use a properly certified oil, your warranty should be safe.
Should I use additives?
Lechien cautions that many commercially available oil treatments are designed for four-stroke engines and were never meant to be mixed with gasoline. These additives could leave harmful residue when burned in a two-stroke engine. Other additives may interfere with the way the oil was intended to perform.
"When we design an application we take a broad spectrum of things into consideration," Lechien says. "When you put in an additive you may be diminishing the effectiveness of the components."
How much oil should I mix with my gasoline?
If your watercraft does not have an oil-injection system, your owner's manual should specify the correct premix ratio for your engine. A ratio of 50:1 means 12.5 gallons of gasoline to a quart of oil, 6.25 gallons to a pint, or just over 3 gallons to 8 ounces. Measuring devices such as a Ratio Rite can help you get the proper mix. Since not using enough oil can be disastrous, some people make the mistake of thinking extra oil is a good thing. In fact, too much oil can lead to deposit buildup, piston scuffing and cylinder-wall scoring.
What if I have an oil-injection system?
Oil injection means that you add the oil and the gas separately. You should, however, use a premix during the break-in period in order to provide additional lubrication. Several companies make different oils for injection and premix applications. Injection oil is made to be more fluid so as not to clog the oil injectors, whereas premix can be heavier and therefore may have a slight advantage in extreme operating conditions.
How do I keep my oil flowing?
Every time you add oil; check for foreign particles in the filter in your oil reservoir's fill spout (that is if your craft has one, if it doesn't, you ought to get one). If you find particles, the filter needs to be removed and cleaned with a non-flammable solvent and a brush. Be sure to clean the filter in a well-ventilated area away from sparks and flames.
Air trapped in a hose can obstruct flow and lead to engine damage. If you have removed an oil pump hose for any reason, the pump should be bled when the hose is replaced. Place a rag under the pump and loosen the air bleeder screw until oil flows out, then securely retighten it. If bubbles are visible in the oil line, hook up a flush kit and run water through the cooling hose as if flushing the cooling system.
Remember, start the engine before turning on the hose, keeping it at idling speed until the bubbles disappear from the outlet hose. Remember to turn the water off before stopping the engine, but not more than 15 seconds before. If the bubbles won't go away, take the craft to an authorized dealer and have it checked out. After all, it will be cheaper to have the dealer fix the problem now, than to rebuild your engine later.