This process will be the same on all Sea-Doo jetskis from 130 and up to 260HP Rotax engines. If you look after your Jet ski it will look after you. This means doing some basic preventative maintenance every 12 months.
The Sea-doo 4Tec Rotax engine is a very robust and powerful motor. To keep it in peak performance you will need to replace the spark plugs every year.
Table of Contents
- 1 Tools Needed
- 2 Procedure for Sea-doo GTI 130 spark plug change
- 3 Sea-doo spark plug chart
- 4 Problems you may encounter.
- 5 Conclusion
- 3/8 Socket set with extension bar
- 13/16 inch spark plug socket
- NGK Spark Plugs DCPR8E / 4339 – Sea-Doo Spark plug chart further down.
- Dow corning 111 Molykote 111 Compound
- Can of air
- Time approx 1/2 hour.
Procedure for Sea-doo GTI 130 spark plug change
I like to replace the spark plugs on my GTI 130 every time I winterize it. So this means I take them out and put new ones in during my yearly maintenance. The plugs you require are NGK SPARK PLUGS DCPR8E / 4339.
You will need a long socket extension as these spark plugs are deep down in the engine block. 5 inches and above will work well. The longer the better.
- Disconnect the spark plug ignition coil connectors.
- Remove the ignition coils by twisting and pulling up. They will be a little stiff.
- Use a can to squeeze compressed air into the spark plug housing to blow out any old dirt, oil, or water.
- Use a 13/16 spark plug socket to remove the plugs. Turning anticlockwise will remove them. If they haven’t been removed in a while they may be rusted in tight.
- Lift the spark plugs using one of the ignition coils. Just press the coil over the spark plug to lift them out. It’s a nice mechanics tip I picked up.
6. Use XPS to spray a small squirt into the cylinder block. This will coat the cylinder to prevent rust on the bore if winterizing it.
7. Leave the plugs out and crank over the engine. This will lube up the piston rings as well. Use a rag over the plug holes to capture any excess lube.
8. Use some never seize compound on the spark plug threads to make removal easy next time. Now is a good time to unscrew the top tip of the spark plug and discard it.
9. Reinsert the new spark plugs making sure that the spark plug gap is set to 0.03 inches. I have yet to find one out of specifications but bet to be careful.
10. Hand tighten your spark plugs to make sure you don’t cross-thread any of them. Then use a socket wrench to tighten an extra 1/4 to 1/2 turn. The instructions on the spark plug packaging will explain how much to tighten. For me, these plugs were 1/2 turn after hand tight.
11. Clean all the old Down Corning 111 waterproof paste off the ignition coils and apply a nice new gob of paste just underneath and above the plug connectors terminals.
12. Slide the black rubber disk back up to the top and apply more Molykote (DOW CORNING) 111 to the rubber seal.
13. Insert the ignition coils and line up the connection points and plug them in. Smooth over any excess Down Corning 111 paste.
Congratulations you have just replaced your spark plugs on your Sea-Doo 130HP Jet-Ski. Other more high-performance models will have an engine cover that will have to be removed first.
Below is a great video that explains in great detail how to remove the spark plugs on Sea-Doo 4Tec. Skip to the 3.40-minute mark. Thankyou 3ftDeep.
Sea-doo spark plug chart
GTX LTD 300
Comes with an oil filter.
|GTI 4-TEC |
650CC & 780CC
650CC & 780CC
3D 947 DI
|1990-96||SP, GT, GTS, |
GTX, SPi, SPX, XP
How many spark plugs in a Sea-doo?
All Sea Doo Jet skis have three spark plugs. You must change all three if doing a spark plug replacement.
They tend to rust in over time so change them out every year. It is a small cost to pay for peace of mind.
How often should you change Jet Ski spark plugs?
You should change the spark plug in a Jet Ski every year or 25 hours whichever comes first. These are cheap consumable items that will fail and rust if you don’t change them out regularly.
Problems you may encounter.
Stuck Spark Plug
If the spark plugs have not been removed for a while they may be rusted in position. Try warming up the engine first and then try to remove the plugs. If they are still stuck you will have to use a breaker bar.
Sometimes in extreme circumstances, the spark plug will break or snap. You will have to then use an easy out to remove the plug. Always check for any metal on top of the piston if you break a spark plug.
Tip: Never over-tighten spark plugs otherwise you will have issues removing them on the next service.
Oil in the Spark plug hole.
Sometimes when working on other Jetskis I have found oil in the spark plug hole covering the spark plug. Usually, this comes from a failed rocker cover gasket and it is leaking engine oil into the spark plug area.
If it is only a small amount it is not a big deal. But if it is allowed to cover the ceramic part of the spark plug you can get a misfire on that cylinder. This is because the spark tracks into the engine oil.
You will need a new rocker cover gasket to fix. Otherwise, just drain the oil from the spark plug area after every few rides. A can of air and a rag works great.
Ignition coil hard to remove
If you don’t use Dow corning 111 Molykote 111 Compound the ignition coils can be hard to remove. Make sure to use this as it will also stop water and dirt from getting into the spark plug area.
If you find that the ignition coil is swelling up this means there is corrosion or failure of the coil and it will need to be replaced.
If you have everything ready to go the Seadoo GTI 130 spark plug change removal process should only take 1/2 hour. The cost of plugs are cheap so I buy 9 at a time to get me through a few seasons. The plugs I use are DCPR8E 4339.
Doing this service job yourself will save you a heap of money and it is very easy to do. Once you complete it why not do the oil service change on your Sea-Doo at the same time.
Now get out on the water and have some fun. Maybe we will cross paths one day.
I am a qualified Industrial Electrician for the past 20 years and I love to share my knowledge on home repair jobs.
I love fast toys like Motorcycles, Cars, Jetskis, and Boats so writing about them is easy.
To keeps costs down I do all my own mods, repairs, and servicing. These skills I want to share with everyone. DIY is a skill everyone can learn.