What to Do with a Submerged ATV

How to get water out of an engine

A 4x4 driving through deep water
Getting the water IN the engine is easy. Getting it out, without destroying the engine, can be more of a challenge. (Tobias Titz/Getty Images)

Sucking water into your internal combustion engine is more common than you might think. If you do a lot of offroading and ride through rivers, streams, puddles, and lakes, or if you spend any time riding with people like Travis Pastrana, you are more likely to get water in your engine, especially if you don't have a snorkel.

Warning: If you get water in your engine, DO NOT ATTEMPT TO START IT BEFORE PERFORMING THE STEPS LISTED BELOW.

The problem with getting water in your engine is that your engine was designed to compress air and gas as the piston moves up, ignite it and use the resultant explosion to push the piston back down.

Water can NOT be compressed when the piston moves up. The resulting damage could include a hole in the cylinder wall, a hole in the piston head, blown out valves or a hole in the head. The water will go somewhere, and it will take the weakest route it can find. This is known as a hydrolocked engine.

Getting the water IN the engine is easy. Getting it out, without destroying the engine, can be more of a challenge. First I'll share a few ways you can get the water in your engine so you'll be a bit more prepared while you're offroading and you'll know what to look for and what to avoid.

Riding on an ice covered lake is a great way to get water in your engine. (It's also a great way to freeze your nads off if you fall through, so water in the engine may be the least of your worries at this point.) If the ice is thin and you ride over it, you could fall through.

Unless you're quick to shut the engine off you're almost guaranteed to get water in your engine.

Crossing streams, lakes, and rivers that are too deep is another great way to get water in your engine. Carburetors and air-boxes are typically on the upper end of the engine so you'd have to be pretty deep to get water in there, but it can happen.

Know where your air intake is and be sure to keep that above the water line.

When you cross deep water going too fast you risk splashing water up into the air box and having it get sucked into the engine. It only takes a little bit of water in your engine to destroy it, so be careful crossing deep water too fast.

So when you've got water in your engine, and if you're lucky enough to have it shut itself off before it does any real damage, there are a few steps you should take to clear the water out before you try to start it:

  1. First, drain the fuel tank, fuel lines, and the oil. While it's draining, put a fan on the wiring and dry it out. Remove and clean the carburetor.
  2. Take the plugs out of the engine and turn the motor over to force any water in the cylinder out. Water in other parts of the engine will come out with the oil. Add oil to the engine and turn it over again, without the plug in. Let it sit for a few minutes, then check the oil to see if there's any water in it (it will look like a white milky substance if there is water mixed with the oil). If it's there, drain it again and start over until there is little or no white showing in the oil.
  3. Now re-install the spark plug, add gas, then try to start it. You should have a can of ether handy just in case it's stubborn, but don't use too much. If it starts, let it run for a couple of minutes without revving it. Don't ride it either.
  1. After it runs for a few minutes, shut it off, drain the oi,l and change the filter. Run it again for a few minutes then shut if off and check again for milky colored oil. If you have none, you should be good to go.
  2. If you cannot start the engine, you may have already ruined it and you will probably need to seek a professional to repair it, or, more likely, you'll have to replace it.