Dirt Bike Won’t Start After Washing (Problem solved)

Who doesn’t like a clean bike! But some muck is just better left where it is. Don’t panic. We’ll get her figured out in the next few minutes.

The top 5 reasons a dirt bike won’t start after washing includes:

  1. Spark plug wet
  2. Spark plug flooded
  3. Water in fuel system
  4. Wet electrics
  5. Hydro-locked engine

In this post, you’ll learn the top 5 reasons your bike won’t start after washing, how to diagnose them and what you can do to fix them right now.

Wet Plug

Your spark plug lives at the front of the bike and is usually protected by a rubber boot. The boot sits snug around the plug and protects against water splash and flying debris.

While the rubber boot is weatherproof, it’s not waterproof, so directing a power washer at the plug will cause water to soak the plug, plug hole, and cap resister.

Drying the plug will solve the problem. Compressed air is the fastest way to dry out the plug, but a shop towel and some wd40 will get the job done too.

Flooded Plug

What’s a flooded plug? Cranking an engine that won’t start causes gas to soak the plug. If water caused your spark plug to become damp, cranking compounds the problem.

Power washers can produce 2000psi and more, which is plenty powerful to penetrate the intake ducting and enter the cylinder. A water-soaked plug electrode won’t produce a spark.

Water In Fuel

Water in the fuel system will stop your bike dead. Power washing around the fuel cap and vent can cause water ingress. Draining the fuel bowl and changing the filter should get you back rolling.

Wet Electrics

Electrics don’t like water, solenoids, relays, fuses, sensors ignition switches. Dry out all the electrics using compressed air or wd40 will help drive out water.

Check also that none of the electrical connectors are disconnected.

Hydro Locked Engine

Laying your bike on its side to power wash the skid pan is a common mistake to make. Gas and oil can easily move into and fill the cylinder. Oil and gas won’t compress, so depending on how much flowed in, your piston may not move.

In addition, your spark plug is wet.

How to diagnose? Remove the spark plug, and turn over the engine slowly. If gas sprays from the cylinder, you found your problem.

How to fix it? With the plug removed, crank over the engine to dry out the cylinder. Dry the plug or replace it.

Check the oil level and start the engine, the engine will smoke, but it will clean.

Power Washing

Power washing can do a lot of damage. It washes protective grease from chains, and the pressure of the water can penetrate bearings and seals, causing rust and premature failure.

I don’t like to power wash using high pressure. There’s just too much risk of damage.

Before washing, spray the electrics with wd40 and turn the pressure down. Avoid laying your bike on its side.

You may find the following posts useful:

Okay, to leave bike in the rain?

Start a flooded bike

Will bike start without a kill switch?

Will dirt bike start without an air filter?

John Cunningham

John Cunningham is a certified mechanic and writer on ATVFixed.com. I’ve been a mechanic for over twenty-five years, I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of ATV ownership, from maintenance & repair to troubleshooting.

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