Sierra Ignition Pack 18-99315 for Yamaha 3 Cyl 70 HP 1984-1991 Outboards, Replaces 6H3-85540-10-00

The Sierra 18-99315 Ignition Pack is a replacement CDI-style ignition module built for Yamaha 3 cylinder 70 HP two-stroke outboards, Model ET and TLN. The ignition pack controls spark timing and delivery to the engine's cylinders, and a failing or worn unit can cause hard starting, misfiring, loss of power, or a complete no-spark condition. Installing a correctly matched ignition pack restores the factory triggering signal to the coils so the engine fires on schedule across the full RPM range.

This unit is designed as a direct fitment replacement for the factory ignition pack used on the specified Yamaha 70 HP 3-cylinder engines, matching the OEM electrical connections and mounting so it can be swapped in without modifying the outboard's wiring harness. It is intended for boaters and marine technicians replacing a failed or intermittent ignition pack as part of an outboard tune-up or ignition troubleshooting repair.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99315
• UPC: 808282396138
• Weight: 0.9 pounds
• Fitment: Yamaha 3 Cylinder 70 HP, Model ET, TLN, 2-Stroke, 1984-1991
• OEM Cross Reference: 6H3-85540-10-00, 6H3-85540-11-00, TIA03-12, TIA03-12A

Fitment

• Yamaha 3 Cylinder 70 HP outboards, Model ET and TLN, 2-Stroke, 1984-1991

Replaces (OEM)

• 6H3-85540-10-00
• 6H3-85540-11-00
• TIA03-12
• TIA03-12A

Frequently Asked Questions

What does the Sierra 18-99315 ignition pack fit? It fits Yamaha 3 cylinder 70 HP two-stroke outboards, Model ET and TLN, from 1984-1991.

What OEM part numbers does this ignition pack replace? The Sierra 18-99315 replaces Yamaha OEM numbers 6H3-85540-10-00, 6H3-85540-11-00, TIA03-12, and TIA03-12A.

How much does the 18-99315 ignition pack weigh? It weighs 0.9 pounds.

Will this ignition pack work with a different horsepower Yamaha outboard? No, the Sierra 18-99315 is built specifically for the Yamaha 3 cylinder 70 HP two-stroke, Model ET and TLN; other horsepower or cylinder-count engines require a different ignition pack.

Is this a direct plug-in replacement, or does the wiring need to be modified? The 18-99315 is a direct fitment replacement for the factory unit on the specified Yamaha 70 HP engines and connects using the existing OEM wiring.

What symptoms indicate the ignition pack needs to be replaced? Hard starting, misfiring, a loss of power at higher RPM, or a complete no-spark condition on the Yamaha 70 HP 3-cylinder engine are common signs the ignition pack, such as the 18-99315, has failed.

Does the Sierra 18-99315 include mounting hardware? The listing covers the ignition pack unit itself; check your existing hardware and wiring harness when installing the 18-99315 on your Yamaha 70 HP outboard.

Can I cross-reference this part using my old Yamaha ignition pack's number? Yes, if your old unit is stamped 6H3-85540-10-00, 6H3-85540-11-00, TIA03-12, or TIA03-12A, the Sierra 18-99315 is the correct replacement.

Is the 18-99315 a genuine Yamaha part or an aftermarket unit? The 18-99315 is a Sierra-branded ignition pack manufactured to replace the OEM Yamaha unit rather than a factory Yamaha part.

Does this ignition pack fit both ET and TLN model outboards? Yes, the Sierra 18-99315 is designed for both the ET and TLN models of the Yamaha 3 cylinder 70 HP two-stroke outboard.