How To Test 2 Stroke Cdi With Pickup -stator -magneto

How to Test a 2-Stroke CDI with Pickup, Stator, and Magneto

Testing a 2-stroke CDI unit can seem daunting, but with a systematic approach and the right tools, it's manageable. This guide will walk you through the process of testing your CDI, along with its associated components: the pickup coil (also known as the pulse generator), stator, and magneto. Remember, safety is paramount. Always disconnect the battery before starting any electrical work on your engine.

Understanding the System: CDI, Pickup, Stator, and Magneto

Before diving into the tests, let's briefly understand how these components interact:

• Magneto: The magneto generates the initial electrical pulse. Think of it as the power source for the whole ignition system.
• Stator (in some systems): Some 2-stroke engines utilize a stator coil in conjunction with the magneto. The stator provides additional power or specific signals. Not all 2-stroke engines have a separate stator.
• Pickup Coil (Pulse Generator): This coil detects the position of the flywheel and sends a signal to the CDI. It's crucial for precise timing of the spark.
• CDI (Capacitor Discharge Ignition): The CDI unit receives the signal from the pickup coil, amplifies it, and triggers the spark plug at the precise moment for combustion.

Tools You'll Need

• Multimeter: Essential for checking continuity, resistance, and voltage. A multimeter with a capacitance test function is even better.
• Ohmmeter (often part of a multimeter): To measure resistance in the coils.
• Wiring Diagram: A wiring diagram specific to your engine model is invaluable. This diagram will show you where each wire connects and what component it belongs to.
• Test Light (optional): Useful for quickly checking if a circuit is complete.

Testing the Components

1. Testing the Magneto

The magneto test depends greatly on your specific engine. There are usually two ways to check it:

• Visual Inspection: Look for obvious damage such as cracks or loose magnets.
• Voltage Test (if applicable): If your engine allows for easily accessing the magneto output wires, you can use your multimeter to check for voltage output when cranking the engine. This requires caution, and you might need a helper to crank while you test. Consult your engine's manual for the specific voltage reading you should expect.

2. Testing the Stator (if equipped)

Again, this test depends on your specific engine and stator configuration:

• Visual Inspection: Check for physical damage to the stator windings.
• Resistance Test: Using your ohmmeter, test the resistance of the stator windings according to the values specified in your engine's manual. Incorrect resistance readings indicate a faulty stator.

3. Testing the Pickup Coil

• Visual Inspection: Inspect the pickup coil for physical damage.
• Resistance Test: Use your ohmmeter to test the resistance of the pickup coil. Your engine's manual will provide the correct resistance values. A reading outside the specified range indicates a faulty pickup coil.

4. Testing the CDI Unit

This is the trickiest part, and often requires more specialized equipment.

• Visual Inspection: Check for any physical damage to the CDI unit.
• Resistance Test (limited): Some basic resistance tests can be performed on the CDI's terminals, but this often isn't conclusive. The internal components of the CDI are complex and difficult to test without specialized equipment.
• Spark Test (most reliable): The most reliable way to test a CDI is to perform a spark test. This requires temporarily connecting a spark plug to the CDI's output wire and checking for a spark when the engine is cranked. However, this method requires some expertise, and you'll need to ensure proper grounding to avoid electrical shock.

Interpreting Results and Troubleshooting

If any of your tests reveal values outside the specified ranges in your engine's manual, the component is likely faulty and needs replacement. If all components test correctly, you likely have a problem with wiring, connectors, or a less common problem within the ignition system. If you're unsure how to troubleshoot further, consult a qualified small engine mechanic.

Remember: Always refer to your engine's specific service manual for detailed testing procedures and specifications. The information provided here is for general guidance and may not apply to all 2-stroke engines. Safety should always be your top priority when working with electrical systems.