The Mercury 96455T18 Trigger Plate Assembly is the ignition timing trigger used on selected later Mercury and Mariner 2.5L V6 two-stroke outboards and 240 EFI SportJet engines equipped with the CDM ignition system.
Mounted beneath the flywheel, the trigger provides the ignition system with the timing reference needed to fire the cylinders at the correct point in the crankshaft cycle. On these engines, the trigger plate works with the flywheel, stator, and CDM ignition modules as part of the complete ignition system.
Mercury lists 96455T18 as the current replacement for 96455A18. Common aftermarket cross-references include CDI Electronics 134-6456-18 and Sierra 18-99397.
What the Mercury Trigger Does
The trigger assembly sits underneath the flywheel and generates timing pulses as the flywheel rotates. Those signals provide the CDM ignition system with crankshaft-position and firing information so each cylinder can receive spark at the proper time.
On engines using mechanical timing advance, movement of the trigger plate is also part of the ignition-timing advance system.
A failing trigger can contribute to intermittent spark, loss of spark on one or more cylinders, erratic timing, difficult starting, misfire, or an engine that breaks up at higher RPM. These symptoms can also be caused by a stator, CDM module, ignition coil, stop circuit, wiring problem or poor ground, so the trigger should be tested before replacement.
Mercury 2.5L V6 Outboard Fitment
The 96455T18 / 96455A18 trigger is used on selected later 2.5L V6 CDM-ignition Mercury and Mariner two-strokes. Verified Mercury application listings include:
- V-135 – 0G960500 through 0T178499
- 140 Jet – 0G960500 through 0T178499
- V-140 International – 0T178500 through 1B226999
- V-150 – 0G960500 through 1B226999
- V-150 EFI – 0G960500 through 0T408999
- V-175 EFI – 0G960500 through 0T408999
- V-200 – 0G960500 through 1B226999
- V-200 EFI – 0G960500 through 0T408999
- XR-6 – 0G960500 through 1B226999
- Magnum III – 0G960500 through 1B226999. MerCruiser Parts
This makes the 96455T18 especially relevant to the later Mercury 135, 140 Jet, 150, 175 and 200 HP 2.5L V6 family, including XR6 and Magnum III applications using the correct CDM ignition configuration.
Mercury 240 EFI SportJet Fitment
The same trigger family is also used on multiple Mercury 240 EFI and 240 EFI M2 SportJet configurations.
Verified listings include 240 EFI M2 Jet Drive powerhead and pump assemblies in the 0E373939 through 0E406399 range, with some pump applications beginning at 0E370718. Mercury also lists the 96455A18 / 96455T18 trigger directly in the 240 EFI SportJet flywheel and ignition assembly.
For SportJet applications, always confirm whether the parts diagram is referencing the powerhead or pump package serial range, because Mercury catalogs both separately.
The 96455T18 is a CDM trigger. CDI Electronics identifies the corresponding 134-6456-18 trigger for 2000–2007 135, 140, 150, 175, 200 and 240 HP SportJet two-stroke applications and specifically notes that it does not include Direct Injection engines.
Part Number Cross References
- Mercury 96455T18
- Mercury 96455A18 – superseded by 96455T18
- CDI Electronics 134-6456-18
- Sierra 18-99397
The earlier 96455A15 belongs to a different trigger family. CDI catalogs 134-6456-15 for certain 175 and 210 HP SportJet engines, while 134-6456-18 corresponds to the later 135–200 HP V6 and 240 SportJet CDM applications.
Buckshot Racing #77 Diagnostic Tech Tip
Do not replace a trigger solely because an engine has a no-spark condition.
Before condemning the 96455T18, inspect the trigger wiring and connector, engine grounds and harness routing. Then test the ignition system using the proper Mercury service procedure and DVA specifications.
A six-cylinder no-spark problem can originate in the stator, stop circuit, wiring or common ignition supply, while an intermittent or cylinder-specific problem may involve the trigger, CDM, coil or associated wiring.
Also inspect the trigger plate mechanically. It must move correctly with the timing linkage without binding, rubbing beneath the flywheel or pulling on the trigger leads.
The Mercury 96455T18 Trigger Plate Assembly is the correct replacement for 96455A18 on compatible later Mercury and Mariner 2.5L V6 CDM ignition engines and Mercury 240 EFI SportJet applications. Verify the serial number and ignition configuration before ordering for accurate fitment.
Contact Mike Hill at +1-714-697-1716 for tech support.