Caltric Starter for John Deere 100 Series Tractors — 12V CCW, 14‑Tooth Hardened Steel Gear (D100/D105/D110/D120)

Caltric replacement starter built to fit John Deere 100‑series lawn tractors (D100, D105, D110, D120) — 12V, CCW rotation, with an improved 14‑tooth steel drive gear.

If your John Deere 17.5–21 HP tractor is struggling to crank or the original starter has worn teeth, this Caltric unit offers a direct-fit aftermarket replacement. It matches key specifications and common OEM part numbers so it installs with minimal modification. The improved steel 14‑tooth gear is designed for greater durability than softer original gears, and the 12‑volt, counterclockwise (CCW) rotation aligns with the factory configuration for these models.

Will this starter fit my John Deere 100 series tractor?

Check model and engine details before ordering: this starter is intended for John Deere D100 (17.5 HP), D105 (17.5 HP), D110 (19.5 HP) and D120 (21 HP) units in the 100 series. Confirm the rotation (CCW) and tooth count (14) match your existing starter to avoid compatibility issues.

• Fits models: D100, D105, D110, D120 (100 series)
• Engine power range: 17.5–21 HP
• Rotation: 12V, counterclockwise (CCW)
• Drive: 14‑tooth improved steel gear
• OEM-referenced part numbers included for cross-checking

How durable is the improved 14‑tooth steel gear?

The starter uses a hardened steel 14‑tooth drive gear rather than a softer material, which helps resist chipping and premature wear under load. That upgrade targets longer service life and more consistent engagement with the flywheel, especially on older tractors where starter engagement quality is critical.

• Hardened steel gear resists wear and tooth rounding
• Improved engagement with flywheel teeth reduces slipping
• Designed for repeated starts across typical lawn tractor use

What electrical and mechanical specs should I confirm before replacing?

Ensure your tractor’s electrical system is compatible: this starter runs on 12 volts and is engineered for counterclockwise rotation. Physically compare mounting points, electrical terminals, and the gear tooth count to your original unit to confirm a straightforward replacement.

• Voltage: 12 V standard automotive/mower system
• Rotation: CCW (counterclockwise)
• Mount pattern and terminal placement designed for direct-fit swap
• Part numbers for cross-reference: 593934, 693551, BS-593934, LG693551, SE501848, MIA13018

Are there installation tips or things to look out for?

Before removing the old starter, disconnect the battery to avoid short circuits. Compare the posted product picture carefully to your existing starter—verify stud/bolt locations and the gear profile. If the flywheel teeth are damaged, replace or repair them first to prevent new starter gear damage.

• Always disconnect battery prior to work
• Match gear tooth count and rotation before purchase
• Inspect flywheel teeth for damage to prevent rapid gear wear
• Keep hardware and wiring routing identical to factory setup

Who is this for? This Caltric starter is intended for owners, repair shops, and DIY mechanics servicing John Deere 100‑series lawn tractors that require a 12V CCW starter with a 14‑tooth gear. It suits users who need a robust replacement matching OEM specifications and common part numbers (e.g., 593934, 693551, BS593934). If you want a direct‑fit aftermarket option with an upgraded steel drive gear, this unit is a practical choice — just verify fitment against your tractor before ordering.