12V 9-Tooth Starter Motor 23300-FU410 – Verified Fitment for Nissan K15 K21 K25

Verified Variant Fitment — every cross-reference number checked against engine serial ranges before shipment, confirmed on the Nissan K21 spline and mounting pattern.

Technical Specifications

Application Suitability

Why One Part Number Ships in Multiple Variants Across K-Series Engines

The starter motor must match not just the engine family but the specific build variant within a serial range.

Working from the Guangzhou parts hub for years, I have handled inquiries where the 12V Starter Motor for Nissan K15 K21 K25 cross reference looked identical on paper. The Nissan K21 engine, for example, went through running changes where the pinion gear tooth profile and mounting bolt circle shifted slightly between production batches. A unit stamped with the same base number may carry a different spline engagement depth or a shifted solenoid terminal position. Buyers pulling a worn unit off a machine often find the nameplate unreadable, leaving only the engine model as a starting point. [NEED_CITE: Nissan K-series engine running changes across production serial ranges]

Mapping Engine Serial Ranges to the Correct Starter Variant

Identifying the right 12V Starter Motor for Nissan K15 K21 K25 replacement starts with the engine serial plate or the machine model plate when the engine tag is gone. The K15, K21, and K25 share a common block architecture but differ in flywheel housing dimensions and ring gear tooth pitch. We cross-check the serial range against known variant breakpoints — specifically whether the unit uses the earlier or later mounting flange pattern — before confirming fitment.

Interface Dimensions That Decide Whether the Unit Bolts On

Beyond the part number, the physical interfaces determine installation success. The mounting bolt-hole spacing must fall within ±0.05 mm of the bell housing pattern. The 9-tooth pinion must match the flywheel ring gear pitch exactly; even a half-millimeter deviation in engagement depth causes the gear to chatter without cranking. The solenoid terminal orientation affects whether the existing wiring harness reaches without stretching or adapters. [NEED_CITE: starter motor mounting interface tolerance standards for industrial engines]

Reading the Specifications for Real-World Cranking Performance

The 12 V rating matches the standard electrical system in most compact equipment running Nissan K-series power plants. The 1 kW output provides sufficient cranking torque for engines in the 2.0 to 2.5 liter displacement range under normal ambient conditions. Clockwise rotation aligns with the K-series cranking direction; a reversed-rotation unit would spin freely without engaging the flywheel. The 9-tooth pinion geometry corresponds to the ring gear module specified in Nissan service documentation for these engine families. These four parameters together define whether the unit will physically turn the engine over on the first attempt.

What Happens When the Cross-Reference Is Close but Not Exact

A starter that bolts on but carries the wrong tooth count or spline depth creates problems that show up immediately or within weeks. The pinion may partially engage, producing a grinding noise and accelerated ring gear wear. A solenoid with mismatched terminal spacing forces field wiring modifications that compromise connection reliability under vibration. In dusty or humid operating environments typical of construction and agricultural sites, these marginal fitments fail faster than clean replacements. The machine goes back down, and the buyer orders a second unit — doubling the parts cost and extending downtime. [NEED_CITE: starter motor engagement failure modes in off-highway equipment]

Why Buyers Source This Starter Through Our Desk

Our own production lines and qualified sourced supply carry the same quality control and warranty terms under one account. Eight product categories mean a complete engine auxiliary order — starter, alternator, sensors, gaskets — consolidates into a single shipment. Single-piece orders ship without minimum quantity barriers, which matters when one machine is down. Identification works from a part number, machine model, photograph, or nameplate image. Cross-reference verification covers superseded and alternate numbers across the full OEM list. Samples ship for fitment confirmation before any bulk commitment, so buyers see the physical interfaces before committing to fleet quantities.

Documentation & Verification

• Commercial invoice listing each starter motor by verified cross-reference number
• Compatibility sheet mapping engine serial ranges to correct flange variant
• Dimensional inspection record covering bolt pattern and pinion engagement depth
• Warranty terms covering manufacturing defects for 3 to 12 months
• Packing photographs showing unit condition before crate closure
• HS code and customs classification support for international shipment

Fitment Check Before Installation

• Compare 9-tooth pinion profile against removed unit before bolting on
• Measure mounting bolt-hole spacing against bell housing pattern with calipers
• Confirm CW rotation direction matches engine cranking requirement
• Verify solenoid terminal position aligns with existing wiring harness reach
• Test engagement depth by hand-cranking the pinion against the ring gear
• Report any mismatch immediately with photographs for cross-reference recheck

Request Fitment Confirmation Before Ordering

Send the engine model, serial number if available, or a photograph of the existing unit nameplate and mounting flange. Our technical team will verify the correct variant from the cross-reference list and confirm interface dimensions. For fleet orders across mixed K15, K21, and K25 equipment, provide the machine model list so we map each unit to the right starter variant before quoting.

Frequently Asked Questions

Q: How do I confirm this starter fits my Nissan engine when only the machine model is known? A: The machine model lets us trace back to the engine family and production period. We then cross-reference the known starter variants for that serial range, checking tooth count, rotation direction, and mounting pattern. If the nameplate is gone, a photograph of the old unit's flange and pinion helps narrow the variant. We confirm fitment before shipping.

Q: Multiple OEM numbers are listed — which one applies to my specific engine serial range? A: Several of those numbers are superseded or alternate references assigned during different production periods. We check your engine serial against the variant breakpoints to identify which original number was assigned at the factory, then confirm the aftermarket replacement covers that exact configuration including flange pattern and terminal type.

Q: Can I get a sample to test fitment before placing a full order? A: Yes. We ship single samples so you can physically check the 9-tooth engagement, bolt-hole alignment, and solenoid terminal position on your machine before committing to bulk quantities. This eliminates the risk of a full order arriving with a variant mismatch across your fleet.

Q: My old part number is discontinued — is there a verified replacement path? A: The cross-reference list includes superseded numbers that were replaced during production running changes. We verify that the replacement covers the same mounting interface, tooth geometry, and electrical specification. The discontinued number is mapped to the current verified variant with dimensional confirmation before shipment.

Q: The mounting bolt pattern looks different in photos — how do I verify before shipping? A: Send a photograph of your old unit's mounting flange alongside a ruler or caliper reading. We measure our unit's bolt-hole spacing within ±0.05 mm tolerance and return a comparison image. If the pattern does not match, we trace the correct variant through the engine serial range rather than shipping a close-but-wrong unit.