If your ATV isn’t getting spark from the spark plugs at the engine, you’re basically dead in the water. This can be an extremely frustrating spot to be in because the engine won’t turn over and won’t give any hints as to why. I’ll tell you exactly how to check for spark on an ATV, and if you’re not getting any, how to diagnose the electrical components to find out exactly where your problem is.
Quick ATV Spark Check
To quickly tell if your ATV is getting spark, remove the spark plug from the engine. Reinsert the plug back into the coil wire. Hold the electrodes of the spark plug close to the engine to ground it, and try starting the engine. If you see spark coming from the end of the spark plug, your ATV engine is getting spark.
Keep in mind, on some models you will need to have the handle bar switch in the run position and the rear brake applied. Look for any other red buttons or kill switches that might have been pressed. A lot of quads have fail safes you need to think about when trying to start the engine.
If you have a hard time being able to tell if you can see a spark or not, you could always have a buddy hold the electrodes of the spark plug. If he yells when you try to start the engine, you have spark.
Why An ATV Has No Spark
There are a few reasons an ATV won’t be getting spark from the spark plugs. The electrical systems on these quads can get a little tricky sometimes. Your best bet is to just check one thing at a time making your way down the list until you’ve found your problem.
The most common reason an ATV is getting no spark is a bad spark plug, either the wrong plug all together or just not gapped correctly. Or the spark plug just went bad, that happens quite often and it’s normal.
If you find out you need to replace the spark plug, you can usually find them easily on Amazon here: ATV Spark Plug.
If you know your spark plug is good and gapped correctly, then you’ll want to check for a loose wire, a bad switch, a bad connection, the ignition coil, or a problem with the stator. Lets go over how to check these one by one.
ATV Loose Wire, Bad Switch, Or Bad Connection
First, you’re gonna want to check the condition of the spark plug wire or ignition coil wire. This is the wire that hooks up to the spark plug when it is bolted into the engine. Sometimes these wear out because the wire itself is usually exposed to dirt, rocks, and debris while riding.
If the spark plug wire looks good, the next step is to check for bad connections or bad switches. To do this, disconnect the main electrical connector coming out of the engine. Doing this will unhook the kill switch, ignition switch, and all the wiring associated with those switches. Check to see if you get spark now.
If you got spark after unhooking the main electrical connector, then your problem is one of those switches or the wiring for one of those switches. Now your task is to go through and disconnect each switch one at a time to find the problem part. It will help to have an ohm meter to check each switch and each wire separately.
How To Test An ATV Ignition Coil
First off, you’re going to need a digital multi-meter to test the electrical components of your ATV. If you don’t know what that is, check out this Fluke 115 Compact True-RMS Digital Multimeter on Amazon. That’s the one I have and use, and I recommend it if you’re in the market for one.
You will also need basic tools to get the ignition coil on and off the machine. If you want to be extra safe, you could unplug the battery before starting. But I find it’s ok to just unplug the wiring to the ignition coil before removing it.
To locate the ignition coil, simply follow the wire connecting to your spark plug. Once you have the ignition coil out, you can hook your multi-meter up to it to begin testing. Start by testing the primary side of the ignition coil, where the ignition coil was wired, not the side that goes to the spark plug.
You should see between 0.2 and 5 ohms of resistance. That is a wide range because it varies from machine to machine. It’s best to look through your service manual to see what your ignition coil should read on its primary.
Next lets test the secondary side of the ignition coil. This is the side with the spark plug caps. If your ignition coil has two spark plug caps, simply put the red test lead in one and the black in the other. Look for around 16k ohms resistance, but again you should check your service manual for your specific measurements.
If you only have one spark plug cap, you will take one multi-meter lead and connect to the spark plug cap and the other to the primary side power connector.
Use the spark plug cap as if it’s the negative side of the primary for this test with that type of ignition coil.
How To Test An ATV Stator
Again you will need a multi-meter and basic hand tools to remove the stator. You either have a single phase or a three phase stator. Three phase is the most common, and probably the type you have.
To make sure, check the wiring harness coming from your stator, If you see group of three wires of the same color (usually white, yellow, or black) you have a three phase stator. A single phase stator will not have that set of three wires.
To start with the three phase stator, set your multi-meter up for ohms. Now get the connector with those three same colored wires we talked about before. You are going to be testing each of those wires against each other. So leg one vs leg two, leg two vs leg three, and leg three vs leg one.
You can do this by simply inserting the multi-meter leads into the connector. You should typically see between 0.1 – 1 ohms for each measurement. But check your service manual for your specs on your machine.
If your meter reads OL, that stands for open line, and you will need a new stator. To check if your stator is shorting to ground, simply hook one lead to a stator leg (through the connector) and the other to the stator body or chassis ground on your machine. You should not get any reading on your meter. If you do get a reading on any of the legs, you will need to replace your stator.
You can do this testing while the stator is still on the machine if you’re able to access it. I find it easier to remove the stator to do the actual testing, but that can be a pain all on its own.
Sum It Up
That’s it for the most common electrical problems you’ll see with your ATV. It’s usually something like a bad kill switch or loose wire or connection. Hopefully you find your issue with out too much trouble.
Electrical problems can be some of the most time consuming. If you have the money to spare, it may be worth it to just bring your machine to a shop if you don’t feel like messing around with all the potential causes.
Even then, it doesn’t hurt to quickly look over some connections before calling in a professional.