Autolite AR3910X Spark Plug for Briggs LO206, Animal & Clone Kart Engines

The Autolite AR3910X is one of the most commonly run spark plugs in Briggs LO206, Animal, and clone kart engines for a reason. It delivers a clean, consistent spark that holds up through long sessions, heat cycles, and tight race-day tuning windows.

This order is for a single plug and is a direct replacement for the OEM spec used in many sealed and semi-sealed kart classes. Racers like it because it resists fouling, stays stable under compression, and gives predictable throttle response when jetting is close.

• Fits Briggs LO206, Animal, and most clone kart engines
• Direct OEM-style replacement, no guessing on fit
• Handles heat and compression without loading up
• Consistent spark for cleaner acceleration off the corner

Gap matters with any LO206 plug. If you want to get more out of this plug, learn how to read it properly after a run. We put together a simple, racer-focused guide that walks through color, strap timing, and what the plug is telling you.

Read our LO206 spark plug reading guide here

SKU: AR3910X

Frequently Asked Questions

Q: Is the Autolite AR3910X pre-gapped for my Briggs LO206 engine?

A: No, spark plugs should always be checked and gapped to your specific engine builder's or class rule specifications before installation. Never assume a plug is set to the correct gap right out of the box.

Q: How often should I replace my spark plug in a LO206 or Clone engine?

A: While the AR3910X is durable, performance-minded racers often replace their plug every few race weekends or immediately if they suspect fouling or engine tuning issues. A fresh plug ensures the most consistent ignition and throttle response.

Q: Can I use the AR3910X in engines other than the LO206 or Animal?

A: This plug is specifically designed for the Briggs LO206, Animal, and standard Clone platforms. Always verify your engine's thread reach and heat range requirements before installing this plug in a different engine type to avoid internal damage.

Q: What is the best way to read this spark plug for tuning?

A: To read the plug, perform a "plug chop" by shutting the engine off at full throttle and coasting to a stop. Inspect the porcelain color and the ground strap for heat marks. Check our dedicated spark plug reading guide for detailed instructions on interpreting these signs.

Related Products From Vendor

• Autolite AR3910X Spark Plug Case (48 Pack) for LO206, Animal & Clone Kart Engines
• Autolite AR3933 Racing Spark Plug - 14mm / .750" Reach - Briggs Animal
• Autolite AR3910 Performance Spark Plug for Animal Engines
• Autolite AR3924 High-Output Spark Plug for Animal Karts