Aircraft Magneto Troubleshooting:

Common Issues and How to Fix Them

Magnetos are a critical component of aircraft ignition systems, when they malfunction, your engine’s performance and safety are at risk. This guide will help you understand the most common magneto problems, how to identify them, and when it’s time to call in a specialist.

What Is a Magneto and Why Does It Matter?

A magneto generates electrical energy independently of the aircraft’s battery or alternator. It delivers high-voltage current to the spark plugs at precisely the right moment to ignite the fuel-air mixture in each cylinder. If a magneto fails, engine performance can suffer or stop completely — making regular inspections and fast troubleshooting essential.

⚠️ Common Signs of Magneto Problems

1. Engine Misfire or Rough Running

• Cause: Fouled points, worn rotor or gear, cracked distributor block, faulty condenser.

• Fix: Disassemble and inspect internal parts. Replace damaged components. Re-time the magneto correctly.

  
  

2. Hard Starting

• Cause: Weak spark at low RPM due to a worn impulse coupling or broken spring.

• Fix: Test impulse coupling engagement. Overhaul or replace if needed.

  
  

3. Excessive RPM Drop During Magneto Check

• Cause: One magneto is underperforming or not firing properly.

• Fix: Perform a spark plug lead check. Test spark plugs, leads, and magneto output.

  
  

4. No Spark

• Cause: Failed coil, cracked capacitor, broken contact spring.

• Fix: Use a magneto test bench to diagnose coil health. Replace faulty components and retest.

  
  

5. Overheating or Arcing

• Cause: Internal moisture, carbon tracking, or debris inside the distributor.

• Fix: Disassemble, clean, dry, and reseal magneto. Replace worn seals and gaskets.

🔍 Troubleshooting Tips from the Shop

At CrossFire Magneto, we recommend the following:

• Always check timing before assuming internal failure.

• Swap spark plugs or leads side-to-side to isolate the fault.

• If your impulse coupling “snaps” inconsistently, inspect it immediately.

• Don't ignore RPM drops larger than 175–200 RPM during runup.

🧰 When to Call a Magneto Specialist

Some issues can be resolved in the field, but more serious or internal problems require tools, testers, and the precision of a certified magneto repair station.

At CrossFire Magneto, we offer:

• 500-hour inspections

• Complete overhauls

• Troubleshooting and diagnostics

• Fast turnarounds (7–10 days)

• FAA compliance with all SBs and ADs

Avoid Problems Before They Start

We recommend following manufacturer guidelines and performing a 500hour inspection to catch wear and electrical failures early. It’s far less costly than a full engine issue later on.

📞 Need Help? Contact CrossFire Magneto

Have a magneto concern? Let us help you troubleshoot and get back in the air safely.

🔗 Contact us now or call us directly. +1 (754)-272-1780 info@crossfiremagneto.com