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 you 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.
First drain the fuel tank, fuel lines and drain the oil. While it's
draining, put a fan on the wiring and dry it out. Remove and clean the
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 now white showing in the oil.
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.
After it runs for a few minutes shut it off, drain the oil 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.
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.