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Checking the Cooling System of Your WaveRunner

Checking the Cooling System of Your WaveRunner

Yamaha WaveRunners are built with an open loop cooling system, which exists as a maintenance-free and effective way to cool your engine. However, as your WaveRunner ages with hours of use, the cooling system could be an area that requires servicing. Sometimes, the lines to your cooling system can become clogged or the engine itself needs to be flushed. If you’ve never checked your WaveRunner’s cooling system before, have no fear! This guide will walk you through how to check your cooling line and flush the engine so your PWC continues to operate well without overheating.

Checking the Cooling System Line and Hoses

Blockages directly affect the performance of your cooling system. If it can’t operate at 100%, things begin to go amiss. Your cooling line is the first place to check.

  1. Access the cooling line. If you aren’t sure where this line is, consult your service manual. The standard location is under the seat.
  2. To check the cooling system hoses, trace these one at a time looking for cracks and fraying. If you spot any damage, they’ll need to be replaced.
  3. Connect a garden hose to the cooling line. Turn the hose on and then your WaveRunner. While it idles, inspect the back of the PWC to see if water is being ejected. If there isn’t a consistent stream of water or none at all, your line is blocked.
  4. To rid this blockage, you can either use an air compressor and blow the debris out of the line or hook a garden hose up to the side filters (near the front of the PWC). This will backflush the system to rid it of the debris lodged in there.

How to Flush Your Engine

Sometimes, the engine must be flushed to rid salt, sand, small rocks, and other debris from inside. Riders that take solid care of their boats know to do this at least a few times a season, especially if they ride in salt water. If you persistently ran your WaveRunner in salt water for an entire season without flushing, the salt and dirt buildup can cause overheating. By flushing your engine, you rid your PWC of things that impede the efficiency of your cooling system.

  1. Load the PWC onto a trailer or an area with a decline.
  2. Clean up the ride plate, reverse flow gate, and impeller, as well as the exhaust ports. Dry the engine with soft, clean towels.
  3. Remove the engine cowl. Here, you’ll pull out your WaveRunner service manual to see exactly where the cooling systems drain plugs and flush port are. Once you’ve located them, take the plugs off with a socket and wrench. The flush port’s plug will be made of brass, so it’s easily detectable.
  4. With a flush kit adaptor, remove the plug fitting and install it in the water injection port with an end wrench. Then, put the kit’s hose clap on the adapter hose and connect the hose to the fitting. Tighten the hose clamp up and make sure the on-off valve on the flush kit adaptor is OFF.
  5. Hook up a garden hose to the flush kit adaptor. Turn it on with medium pressure, then start your WaveRunner to let it idle for just a few seconds. During this time, turning on the flush kit adapter valve to allow water to flow into the engine. You should see water coming out of the exhaust port, cooling port, and impeller grate.
  6. To totally flush out your engine, let the engine run for 8 minutes. This will push out salt, dirt, and other small debris. After 8 minutes, turn the water valve off and allow the PWC engine to run a few more seconds before turning it off.
  7. Disconnect the flush kit adaptor and replace all drain and flush port plugs.

Now that your cooling line is clean and engine is flushed, you should see a drastic change in the temperature of your WaveRunner while riding. If you find that your PWC is still running hot, you may have to take it to a Yamaha dealer or reputable service shop. Even if you aren’t experiencing these issues, it’s good practice to know how your cooling system works and ways to rid it of lodged debris and damaging salt. Plus, you’ll have the knowledge to help out a buddy should they start experiencing issues with their cooling system.

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