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Towing Your Jet Ski

When it comes to towing your jet ski, one of the biggest concerns is preventing the engine from filling with water. The majority of manuals state that you can’t tow your jet ski over 5 mph since engine damage, i.e., flooding the cylinders through the exhaust ports, may occur. If that’s the case, then how are people towing their jet skis in the water behind their boats at speeds above 5 mph?

TowSeaDoo001The answer lies in the adding a tow-valve which goes in the main feed line from the pump to the motor. The valve is closed when you want to tow your jet ski to prevent “tow flooding” the engine cylinders via the exhaust cooling passages. Most jet skis scavenge jet pump exit water for engine cooling. The scavenged water is pressurized by the pump so it can flow through the jet ski’s cooling system. Essentially, jet skis bleed pressurized water off the main pump for cooling the engine because they don’t technically have a water pump.

However, when you go to tow your jet ski, pressure builds because the water intake is greater in size than the pump nozzle outlet. With a smaller outlet than inlet, pressure builds as water starts to flow through the pump when the jet ski is towed.

Unfortunately, this means that the water needs someplace to go, so it starts to flow through the cooling system and if the pressure gets high enough it overcomes the gravity of the exhaust port height. Water continues to push upward through the water cooled exhaust passages that lead to the exhaust port. Once the water has reached the exhaust port it travels to an open exhaust valve that leads to a cylinder with an open valve. At this point the last thing you want to occur happens, the cylinder fills with water.

This is why you need to place a tow valve in the main feed line between the pump and the motor and close it to prevent “tow flooding” your engine cylinders via your jet ski’s exhaust cooling passages. It’s best to check your owner’s manual to see the precautions you should take in order to tow your jet ski in the water as well as the suggested speed to tow.

Towing can be extremely dangerous. If you need to tow your jet ski back to a marina or to shore, you need to make the fact that you are towing perfectly obvious to other boaters. Use signal devices if your boat has them and if not, then wave a brightly colored flotation device to help alert other boaters.

Before your first trip of the season to the water, be sure to drop by Jet Ski Plus so we can show you the appropriate hose to clamp off in the event that you need to tow your jet ski. If your jet ski fills with water or sinks, you’ll want to have it serviced as quickly as possible. If your jet ski’s engine hasn’t been cleared of water or hasn’t been run within a day or two of sinking or filling with water, it’s life could be severely shortened or finished for good.

Do not attempt to start an engine that’s drowned or filled with water. This can result in bending connecting rods or destroying your jet ski’s engine. Before you get in the water this season, make sure you refer to your owner’s manual for the proper direction to turn your jet ski if you flip it over. If you turn it the wrong way after flipping it over, you increase the chances of your jet ski’s engine ingesting a large amount of water.