When your Fourtrax doesn't crank

When trying to diagnose a fail to crank condition there are a few things that you need to look at first. First is the battery. In order to diagnose a starting condition the battery needs to be fully charged and in good health. Most auto part stores can test batteries. Chances are if your battery is more than a couple years old you could just need a battery. ATV batteries typically don't last as long as car batteries.

Once you have confirmed your battery is good the next step is to check the terminals. If they have corrosion on them you will need to clean them. An easy way to clean battery terminals is with baking soda paste and a wire brush. In a small dish mix 3 tablespoons of baking soda and 1 tablespoon of warm water. Dip the wire brush in the paste and use it to scrub the terminals. Wipe the terminals off with a clean shop towel and check to make sure all the corrosion is removed. If the corrosion extends far into the terminal leads you may need to replace them.

It is always important to be sure the quad is in neutral. Also ensure that the run switch is positioned in the run position and not in the off position.

Next you should check the switch that controls the starter. Typically it is located on the handle bars and in the case of the TRX300 it is located by the left hand grip. Using a multi-meter you can test this at the starter solenoid. In the case of the TRX300 there will be two small gauge wires going to the solenoid. Remove them and place a multi-meter lead on each. Having an assistant press the button check for continuity. There should be no connection when the switch isn't pressed and a connection when it is. Reconnect the wires after the test is complete. If the switch tests bad replace it.

Once we know that the battery, cables, and start switch are up to the task but the quad is still not turning over we need to look at the solenoid and starter.

The starter solenoid is basically an electronic switch that allows a low current device like the starter button on your handle bar control a high current device like the starter. Obviously running all that current the starter requires through the little wires on the starter switch would cause the wires to overheat. However when solenoids go bad often times they will click but not transfer power to the starter or make no sound at all. Now just because it clicks doesn't mean its bad. Solenoids will normally click but they will also close the circuit for the starter, creating a circuit.

The easiest way to test whether the solenoid or the starter is bad is to bypass the solenoid by jumping it's leads. On top of the solenoid you will see two posts in which the starter and battery leads connect. Using a screw driver you want to momentarily short these two leads together. You will often times see a spark. If the starter motor begins to turn it is a good indication that your solenoid is bad. Solenoids can be found for around $25 online and a few auto part stores are now carrying them for about the same price.

If it doesn't then you need to check to make sure you wires are well connected to the starter. If the wires have a connection to the solenoid then it is a good bet that your starter is dead and is in need of rebuild or replacement. Starter motors can be found for around $150 online.