Excavator Starter Motors
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121256-77010 is a Yanmar starter reference for a 12V 2.0kW clockwise 15-tooth starter used across 3TN82E/4TN78/4TN82/3TNV88/4TNV88 engine families. Representative compact excavator applications include Komatsu PC35, PC40 and PC50 families. Confirm the full number, Hitachi label, pinion, flange, engine suffix and machine serial.
Send the machine model, engine model or nameplate photo so our team can confirm compatibility before shipment.
| Relationship | Reference family | Number |
|---|---|---|
| Primary Equipment Part Number | Yanmar starter reference | 121256-77010 |
| Related Yanmar Reference | Verify exact revision | 129130-77010 |
| Related Hitachi Family | Verify exact suffix | S13-294 / S13-94 / S13-124 / S13-132 |
Product fitment guide
Quickly compare the reference number and recorded machine applications. Use the original photos and the checklist before ordering.
Part identification
Formatting aliases are the same number written differently. Related assemblies and remanufactured numbers are not presented as direct interchanges.
Product summary
Before ordering
Machine fitment
3 model references
Compatibility lists identify searchable model families, not every production serial range. Confirm the original part number and machine serial number before purchase.
Quick fitment answers
Recorded compatible model references include Engines: Yanmar 3TN82E / 4TN78 / 4TN82 / 3TNV88 / 4TNV88, Representative machines: Komatsu PC35 / PC40 / PC50 families, Fitment limitation: Confirm number, label, pinion, flange, suffix and serial. Confirm the complete part number and machine serial range before ordering.
Related assembly numbers (not direct interchanges): 129130-77010, S13-294 / S13-94 / S13-124 / S13-132.
Confirm voltage and power rating against the original starter nameplate. Compare mounting-hole pattern, flange position and overall body orientation. Confirm pinion tooth count and rotation where those values are specified. Send clear photos of the original unit and connector layout when requesting a quote.
