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What To Do If Your ATV or UTV Goes Underwater? How To Flush ATV?

Did you hit that deep mud hole that was just TOO DEEP and now you majorly regret sending your machine through it. I understand because I’ve been there, done that. It happens all the time and I am here to help.

What to do if your ATV or UTV goes underwater? If you have water in your air box and you are certain there is water in your engine, do NOT try to crank the engine. Get someone to pull you back. The first thing you should do is clean the air box and air filter of any mud that entered. The next step is to remove your spark plugs and turn over the engine to shoot out any water that is on top of the pistons. Spray some WD-40 in the spark plug holes to dissipate any water that may remain and then put the spark plugs back. If your ATV is belt driven, you will need to remove the belt case and let that dry out as well. The next thing to do is flush your engine and differentials to remove any water within. After this is done, make sure your air filter is dry and your ATV should be back to normal and ready to ride again.

If your ATV or UTV was completely underwater for an extended period of time, then you will want to flush your engine and differentials. Flushing your engine and other components is critical which is why I explain below.

How To Flush An ATV Engine?

When getting water inside the engine of your expensive atv or utv, it is crucial you flush the engine properly of any water that may be inside. Water can hydrolock your engine meaning that you will need a new engine. So here are the 10 steps to flushing your ATV engine.

  1. Drain all water and oil from engine.
  2. Fill engine with diesel fuel.
  3. Let engine idle for 2-3 minutes.
  4. Drain fuel from engine.
  5. Repeat steps 2-4.
  6. Fill engine with cheap oil and change oil filter.
  7. Run the engine for 5-10 minutes.
  8. Drain the oil and replace the oil filter again.
  9. Fill engine with premium oil of your choice.
  10. Try to avoid those deep holes next time and have fun!

Supplies Needed:

  • 2-3 gallons of diesel fuel
  • Oil Filters (2)
  • Cheap Oil (recommended amount)
  • Premium Oil (recommended amount)

How To Flush ATV Differentials?

  1. Drain the water and oil from your differentials.
  2. Lift tires off the ground.
  3. Fill differentials with diesel fuel.
  4. Rotate the tires by hand for 30-45 seconds.
  5. Drain the fuel.
  6. Repeat steps 3-5.
  7. Fill your differentials with a premium 80W-90 gear oil.

Supplies Needed:

  • 1-2 gallons of diesel fuel
  • 80W-90 Gear Oil (Recommended Amount)

Flushing your ATV differentials is a much easier process than flushing your engine. I actually recommend changing your differential fluids every 4-5 rides. If you do not drive through deep water and mud each ride then you can extend that frequency. The seals that keep your differential fluid inside are only designed to keep that thick oil inside, NOT to prevent water from coming in. Water WILL find its way inside your differentials especially driving through extremely deep water.

How To Clean Your Air Filter Box and Air Filter?

There is no rocket science behind this, all that is needed is a wet towel to wipe down the inside of your air filter box. Spray out your air filter with a water hose and/or air filter cleaner and then hang it up to dry. After it drys, spray it with some air filter oil to help collect dirt, dust, etc. You may want to wear some gloves when spraying air filter oil because it tends to be sticky and can get messy real quick.

How To Remove Water From The Top Of An ATV or UTV Piston?

If you tried to crank your machine underwater or it sucked in water through your intake, you most likely have water sitting on top of your piston. Luckily, it's quit easy to remove. Take out your spark plug and turn over the engine. As the engine is turning over (it will not start with the spark plug out), you will see water burst from the spark plug hole. The piston is going up and down and will push the water out the top. Next, you want to spray some WD-40 into the spark plug hole which will dissipate any water on top of the piston and prevent the water from creating any rust inside your engine.

What To Do In The Moment Of Your ATV Going Underwater?

Scenario #1

If your exhaust goes under the water and your air intake is above the water then keep the engine running to prevent water from going inside the exhaust. If your engine cuts off at this time, do not try to crank it.

Solution: Get someone to pull you out and make sure there is no water in the air box. If no water, then try to tilt the ATV in the air to drain the water from the exhaust and then crank the engine to shoot out the excess water. If you cannot tilt the machine, you need to remove spark plug and then turn over the engine to get the water out of the exhaust. If you get water in your air box while your engine is running, you need to follow my instructions for flushing an engine.

Scenario #2

If your exhaust is under the water and you know your air intake is about to go under then immediately shut your machine off before the intake goes under the water. This will prevent your intake from sucking water inside of your engine.

Solution: Drain your air box and exhaust (solution #1). The machine may need to be properly flushed depending on depth of water and length of time under.

Scenario #3

Your exhaust and intake are under the water while your engine is running and then the water chokes out the engine.

Solution #3: You need to be pulled back and have your ATV or UTV flushed out properly.


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