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How to Fix a Locked Jet Ski Motor


How to fix a locked up jet ski motor.

It can be disheartening to turn on your jet ski and find that you’ve got a locked motor. With the high costs of professional jet ski repairs and the complexity of engine mechanics, it is easy to feel defeated in this situation. Fortunately, there are some practical approaches to diagnose and fix your locked motor at home with basic tools that you can find in just about every household. 

To fix your locked jet ski motor, you will need to remove the engine’s spark plugs, lubricate the cylinders, apply gentle force to each cylinder, and potentially apply additional force to the mid-sized cylinder to release the engine if it initially doesn’t take. 

To make the procedure of unlocking your jet ski motor as easy and stress-free as possible, we are going to walk you through every step of the process. Keep reading to learn how to unlock your jet ski motor so that you can get yourself back on the water.  

Diagnosing a Locked Jet Ski Motor

Before assuming the state of your jet ski’s motor when it doesn’t turn on, you need to diagnose what the actual issue is and whether a locked motor is behind the problem.

Watch this gentlemen’s overview of the symptoms he was seeing and then we will get back into what needs to be done.

How to tell if your engine is locked. 2007 sea doo challenger 180 4-tec rotax supercharged

If your engine creates a loud cranking sound as you try to start your jet ski, it is most likely because your starter is hitting your flywheel due to lack of lubrication, which is the first sign of a locked motor. Additionally, if the engine does not start, but the electrical components work, you are also likely dealing with a locked motor.

If this is the case, you’ll want to look at your engine’s spark plugs and cylinders next to confirm if locking is the issue, which we’ll cover how to do below. 

Note: Do not attempt to try to start your jet ski again, as this could lead to additional issues—especially if the motor is actually seized. 

How to Fix a Locked Jet Ski Motor

At this point, it has become clear that the probable reason your motor won’t start is it’s locked and will need some repairs. To successfully do so, you will need some tools that you likely have lying around your house.

The following tools will be necessary to complete the repairs of your jet ski’s locked motor:

  • Long screwdriver (or another similarly shaped metal instrument)
  • Socket wrench 
  • Spark plug socket
  • Vice grips
  • Hammer
  • PB Blast or some other type of penetrating oil 

Once you have all of your tools handy, you can begin repairing your engine. The procedure for this is very similar across all jet ski brands and manufacturers but differs slightly depending on whether your motor is turbocharged or supercharged (more on that later). 

The following steps will take you through the procedure of fixing your jet ski’s locked motor:

Remove the Motor’s Spark Plugs

Regardless of the motor type of your jet ski, to begin your repairs, you will need to remove your spark plugs. 

Using your socket wrench and spark plug sockets, remove the plugs. If you find that they are difficult to pry out of place, spray them with some of your PB Blast to loosen their hold. Note: You may need to take out the interior coils of the spark plugs as well. 

Move the Cylinders

For this next step, you will need to reach your jet ski’s drive shaft—for which you will need to utilize your screwdriver and vice grips.

Below is a breakdown of the steps you’ll need to take to move the cylinders on a turbocharged jet ski motor versus a supercharged motor. Just to get you familiar with the process, though, this video from YouTube outlines some of the steps involved:

Sea-doo GTX removing the cylinder

Turbocharged Jet Ski Motor

After successfully removing your spark plugs, take your long screwdriver and insert it inside each cylinder. You want to make contact with your motor’s driveshaft and attempt to create movement in each cylinder.

You will find that the screwdriver will likely not go in even for each cylinder, with one having an especially small depth. Don’t worry—this is not a symptom of a seized motor or any other engine issue; it is simply due to your cylinders’ different angled positions. 

Using your vice grips, connect to the driveshaft of your jet ski and give it a turn. As you turn the driveshaft, observe the cylinder, and look for movement on the screwdriver of each allocated cylinder. If there is no movement, this will be the telltale sign that your motor is locked and will need additional repairs.

Supercharged Jet Ski Motor

To achieve the same result with a supercharged jet ski motor, you will need to remove the hose from the front of the engine fan.

To do so, you will first need to remove the hose clamps and then unfasten the fan’s grommet to have access to the driveshaft. Once you have successfully unfastened the grommet, attach your vice grips to the shaft and look for the same movement of the screwdriver.  

If you happen to find movement in one cylinder and not another, your jet ski likely doesn’t have a locked motor but rather a broken connecting rod. 

Lubricate the Cylinders

What you want to do next is lubricate the interior of each cylinder. You can use your PB Blast or some other lubricating alternative for this purpose. 

Once you have coted each cylinder with lubricant, let it sit for about 24 hours to ensure that the lubricant does its job.

After you have waited for 24 hours, give each cylinder another spray of the lubricant. Then insert your long screwdriver into each cylinder and push down or lightly tap the top of the screwdriver with a hammer. Be careful not to add too much force, as this could potentially damage your pistons and create further problems for your jet ski’s motor.   

From here, the problem may be resolved, but if this fix did not get the job done, there is an additional step you can take to unlock your jet ski’s motor. 

Release Your Locked Motor

To continue fixing your jet ski’s locked motor, you must first assess the cylinders to designate which one will be best for releasing the motor. To do so, take your screwdriver and find which cylinder out of the three has a mid-sized depth.

Even if your screwdriver easily reaches the bottom of the deepest cylinder, you should avoid using it to release your motor, as this increases the risk of damaging your piston. In contrast, if you try this procedure on the cylinder with the least depth, you will not have enough force to release the locked motor. 

Next, you want to take your hammer and use it to tap your screwdriver’s handle to attempt to release the motor. To prevent further damage to your jet ski, strike gently and gradually; you want to use just the right amount of force to release the locked engine. As you continue this process, you will eventually find the locked motor’s sweet spot and successfully release it.

In Conclusion 

Having engine issues like a locked motor with your jet ski is never fun, but it doesn’t mean you have to break the bank at a repair shop or be a professional mechanic to get your watercraft up and running.

Using your basic household tools, you can remove your jet ski motor’s spark plugs and lubricate the cylinders. If you apply enough gentle force to each cylinder, you may be able to release the engine and get back on the water by the next day! 

Teddy Henderson

Teddy is always fiddling with small engines, picking up thrown-out string trimmers or tearing apart dirt bikes. He shares what he learns along the way. Hopefully, you'll have less headaches than he has had by learning from his mistakes.

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