If you own a 4-stroke jet ski, changing the oil is a maintenance item you need to do at least every year or every 50 hours.
Doing regular oil and filter changes is one of the more important maintenance procedures you can do for your watercraft. All jet skis use high-performance engines and need the proper maintenance done to them to keep them running at their best.
This guide will focus more on Sea-Doo, but the steps for Yamaha and Kawasaki are not too different.
Changing the oil in your jet ski is different from changing the oil in your car. For one thing, there is no oil drain plug.
Tip: All jet skis are metric; 8mm, 10mm and 13mm are the most commonly used sizes.
Here is most everything you need:
- Oil change kit.* This includes the oil, oil filter and o-rings. Some kits even come with spark plugs, which you should change too when doing the oil change.
- E10 Torx socket, or a high-end 8mm socket will do.
- Oil Extractor: The long cylinder oil extractors* work the best.
- Oil rags.
You need to make sure you get the correct oil for your jet ski, especially if it’s supercharged. The oil change kits will list the models it’s made for but otherwise consult your owner’s manual.
Steps For Changing Oil
Before you start, make sure the jet ski is out of the water and be sure to level it.
Avoid changing the oil on the lake, boat slip, or hoisted above the water.
There are EPA laws about changing motor oil on the water, and the fine can be quite high.
The Watercraft Journal made an excellent video on changing the oil in their 2018 Sea-Doo RXT-X 300 if you need a video guide:
Step 1: Warm Up The Engine
You need to get the jet ski engine warm, a 15-minute ride on the water will be enough to warm up the engine oil.
Another way is to run the jet ski on the garden hose, as shown how to do here.
Under 2 minutes
For Sea-Doo, you want to stay under 2 minutes while flushing because of the carbon seal, but Yamaha and Kawasaki can stay under 5 minutes.
Step 2: Remove The Engine Oil
Once the engine is warm, you can remove the oil through the dipstick using the oil extractor.
Make sure to remove the oil cap before removing the oil, the cap is often yellow, red, or black.
When you put the hose of the extractor down the dipstick, you want to go all the way to the bottom and then back it out just a hair.
Tip: Don’t buy the electric pump extractors, stick to the long cylinder hand pump extractors*. The extractors that use the hand pump often come with a tank and the tank has the measurements of how much oil you removed. You’ll need to know how much you removed so you know how much to put back.
A Sea-Doo holds a total of about 4.5 quarts of oil, but you’ll only pump out about 3 quarts, and that is fine.
When you get to about 2.5 quarts of oil and the siphon starts to sputter, pull the tube out, put the key on the jet ski, hold the throttle all the way in and turn the engine over for 3 seconds. When you have the throttle all the way in and try to start the jet ski, it gets put in drown mode and keeps the engine from starting. After that, put the tube back in and pump some more oil out. Doing this will allow you to pull more oil out.
Step 3: Replace Oil Filter
Use an E10 Torx socket or 8mm socket to remove the oil filter cap bolt from your Sea-Doo engine.
When removing the old oil filter, I like to set aside the new filter and use its box it came in to put the old filter in to cut down on the mess.
Make sure to seat the new oil filter correctly, note the direction, put it in the same direction you took it out.
Step 4: Replace O-Rings
Replace the filter cap o-rings with new o-rings from the oil change kit.
Note: The o-rings are all different sizes and thickness. So make sure you’re putting the correct o-ring in the correct spot.
Apply a little bit of new oil to the o-rings once you install the new ones.
Once you replace the o-rings and inserted the new oil filter correctly, you can add the cap back on and tighten it down. Do not over tighten, you only want it to be snug.
Step 5: Add New Oil
Using a funnel, add the same amount of new oil that you removed. If you only removed 2.5 quarts of oil, then only add 2.5 quarts of new oil. It’s better to be a little under than a little over; It’s easier to add a little more than to remove a little bit.
The oil extractors often have measurement lines to show you how much you removed.
When you’re done adding the new oil, put the oil cap back on and the dipstick too.
Run the engine for 5 seconds, then turn it off, and check the oil level. You want the oil level to be between the two lines (humps).
If you have too much oil, you need to remove the little bit with the oil extractor out of the dip stick. If you don’t have enough, add more oil with the funnel at the oil cap hole.
Important: Do NOT overfill the oil! You want to be in the middle of the two humps on the dipstick.
Step 6: Check For Leaks
When the oil level is fine, button everything back up and run it on the garden hose for 1 minute.
- You want to check for any oil leaks.
- You also want to check the oil level after running it for a bit.
Note: The oil level will be at a different spot when the engine is cold compared to a warm engine.
Step 7: Replace Spark Plugs
Some oil change kits come with spark plugs.
It’s a good idea to replace your spark plugs when you change your oil. It’s simple to do and can keep future headaches away.
Avoid Fancy Spark Plugs
Do not use fancy spark plugs, stick to the NGK spark plugs the manufacturer recommends.
How regularly do I need to change the oil in a jet ski?
You need to change your jet ski oil every 50 hours or once a year, which ever comes first.
For more maintenance items you need to do, check out my maintenance post here.
Where To Dispose Of Engine Oil?
Many recycling centers, Walmart and Auto Parts stores will dispose of your oil.
Many of those stores will also take the used oil filters.
Do 2-Stroke Jet Skis Need An Oil Change?
Only 4-strokes need to change the oil, the 2-Strokes burn oil that is added to them.
You’ll know you have a 4-stroke because it will have a dip stick located on the top of the engine.
Also, the last 2-stroke Sea-Doo made was in 2007. The first 4-stroke Sea-Doo made was in 2002. The last two digits of your VIN tells you the year your jet ski was made in.
Learn more about the difference of 4-strokes and 2-strokes here.
What Oil Should You Use?
You want to use the manufacturer recommend oil in your jet ski, never cheap out on the oil.
The oil you get for your jet ski is slightly different from the oil for your car. I know others may not agree with me, but trust me, stick with the manufacturer’s oil and filter.
Do You Need To Change The Spark Plugs When Doing An Oil Change?
I recommend you change your spark plugs on your jet ski every year.
For many people, they only change the oil once a year, so changing your spark plugs at the same time is smart.
I know some car guys may think changing your spark plugs on your jet ski every year is overkill, but trust me, it’s well worth it!
Is The First Oil Change Important?
The first oil change of your jet ski is probably the most important oil change you’ll ever do.
Your jet ski's engine is breaking itself in when it's new, this means very-very-very small bits of metal are ending up in the oil. You want to get that oil out at the proper time to keep from wearing the engine out more than it should be, and thus why the first oil change is so important.
Some manufacturers and dealers may even require you to bring it to them for the first oil change as it’s more involved, and they want to make sure everything broke in properly. So don’t be alarmed if this oil change cost more than the others. This first oil change is not always included when you buy a new jet ski.
Depending on the manufacturer, the first oil change can be anywhere from 10 to 50 hours. Consult your owner’s manual to know which one.