YAMAKATO ignition coil module for Honda GX240/GX270/GX340/GX390 — 4‑prong 4‑pin with air gap gauge & spare F6RTC plug

YAMAKATO 30500-Z5T-003 is a four-prong ignition coil module that replaces worn coils on Honda GX240/270/340/390 engines and compatible generators, restoring reliable spark and ignition timing.

If your Honda-powered mower, generator, or outdoor equipment is misfiring, hard to start, or running inconsistently, a failing ignition coil is often the culprit. This YAMAKATO replacement coil is built to match OE fitment and electrical connections for a range of Honda GX engines and numerous generator and equipment models. It includes a 4-pin connector, an air gap gauge for correct installation spacing, and a spare F6RTC spark plug so you can complete the repair in one visit.

Will this coil fit my Honda GX390, GX340, or GX270 engine?

Yes — this module is manufactured to replace OE part numbers 30500-Z5T-003 and 30500-Z5R-003 used on many GX series small engines. Confirm fitment by checking your engine’s part number and connector type: this is the four-prong/4-pin variant used on several consumer and commercial generators and engines.

• Compatible with Honda GX240, GX270, GX340, GX390 family engines.
• Direct replacement for 30500-Z5T-003 / 30500-Z5R-003.
• Designed for engines with a four-pin ignition connector.

How easy is it to install the YAMAKATO ignition coil?

Installation is straightforward for anyone comfortable with basic small-engine maintenance. The module mounts to the engine block similar to the original coil; use the supplied air gap gauge to set correct distance between coil and flywheel magnets. Reconnect the 4-pin plug and replace the spark plug if needed.

• Includes air gap gauge to ensure correct magnet-to-coil spacing.
• Supplied F6RTC spark plug lets you finish the job right away.
• Match mounting holes and 4-pin connector for a direct swap.

Which machines and brands commonly use this coil?

This coil is suitable for Honda engines found in portable generators, pressure washers, engines sold under multiple equipment brands, and some lawn and garden machines. It’s also compatible with several generator model lines and popular equipment brands that use Honda GX series engines.

• Common generator models: EM4000SX, EM5000SXK2, EM6500SXK2 and related units.
• Used by OEMs and replacement parts suppliers for MTD, Cub Cadet and Troy-Bilt machines with matching engines.
• Works with multiple commercial and consumer engine configurations that use the four-pin coil.

What comes in the package and why it matters?

The kit includes the YAMAKATO ignition coil with a 4-pin connector, an air gap gauge to set proper clearance, and one F6RTC spark plug—so you can test and complete a basic tune-up during installation. Having the right gap and a fresh plug reduces troubleshooting time and helps ensure the engine runs as intended after replacement.

• YAMAKATO four-prong coil matched to OEM dimensions and connector.
• Air gap gauge included for correct installation tolerance.
• One F6RTC spark plug in a protective bag to check ignition immediately.

Who is this for: This YAMAKATO coil module is aimed at DIY mechanics, small-engine repair shops, and equipment owners who need a dependable, drop-in ignition coil replacement for Honda GX240/270/340/390 engines and compatible generator models. Choose this part when you want OE-style fit and the convenience of an installation gauge and spare spark plug included with the unit.