No. Matching the starter pinion tooth count is only one comparison point, not proof that a replacement snowmobile starter fits. The supplied catalog lists several nine-tooth units with different pinion diameters, rotation specifications, and mounting arrangements. It does not establish gear interchange from tooth count alone.
Nine Teeth Does Not Identify One Gear Size
These catalog entries all specify nine teeth, but their listed outside diameters differ substantially:
| Starter reference | Listed tooth count | Approximate pinion outside diameter | Listed mounting details |
|---|---|---|---|
| Arctic Cat 0745-052 | 9 | 29.1 mm | Two 5/16-18 mounting studs, not through-holes |
| Polaris 2410889 / 4010965 | 9 | 28.8 mm | Two unthreaded mounting holes, approximately 11 mm diameter |
| Arctic Cat / Yamaha 3020-364 group | 9 | 11.7 mm | Two unthreaded holes, approximately 8.6 mm diameter; mounting-ear spacing approximately 40 mm |
| Polaris 0451411 | 9 | 11.7 mm | Two unthreaded holes, approximately 7.5 mm and 6.5 mm diameter |
The 29.1 mm and 11.7 mm entries provide a direct example of why a tooth-count match cannot establish matching gear dimensions. These measurements describe separate catalog entries, not interchangeable alternatives.
Even matching both count and listed outside diameter leaves questions unanswered. The 3020-364 listing and 0451411 listing both specify nine teeth and an approximately 11.7 mm pinion outside diameter, yet their listed mounting-hole diameters differ. The catalog does not establish interchangeability between them.
Rotation and Mounting Still Need Separate Confirmation
The catalog lists the Polaris 2410889 group and Arctic Cat / Yamaha 3020-364 group as clockwise (CW). It lists the Ski-Doo 420892420 group and Ski-Doo / Lynx 420684560 group as counterclockwise (CCW). All four groups have nine teeth.
Those entries demonstrate that tooth count does not identify the listed rotation. They are not instructions to alter rotation or substitute one starter for another.
Mounting details also remain independent. For example, the Ski-Doo / Lynx 420684560 listing specifies one approximately 6 mm unthreaded hole and one M8×1.25 threaded hole. That differs from the two-stud mounting listed for Arctic Cat 0745-052, despite both having nine teeth.
For Arctic Cat 0745-052, the supplied technical record also reports conflicting rotation information in public catalogs. Rotation must be checked against the reference unit before ordering; its known tooth count does not resolve that conflict.
Missing Gear Data Is Not a Match
Not every listing supplies a reliable tooth count or complete gear dimensions:
- Arctic Cat 0645-183: Tooth count and pinion outside diameter are not reliably listed. The approximately 9.5 × 6.5 mm drive-end dimensions must not be relabeled as a pinion diameter or tooth count.
- Arctic Cat / Yamaha 0745-444: Reliable, consistent tooth-count and rotation data are unavailable. The record identifies pinion 0645-853 as a separate component; its presence in the application information does not confirm inclusion with a quoted motor.
- Arctic Cat / Yamaha 0745-441: Reliable, consistent tooth-count and rotation specifications are unavailable.
- Polaris 2412235 / 2414829: Nine teeth are listed, but the record does not supply a pinion outside diameter.
Do not borrow an unknown value from another starter because it shares a brand, looks similar, or appears nearby in a catalog. The supplied evidence also does not establish gear pitch or complete gear geometry, so it cannot support a gear-interchange conclusion.
What to Request Beyond Tooth Count
For a tooth-count-based comparison, ask the supplier to resolve the specific gear and mounting questions rather than simply confirm that both units have nine teeth:
- Identify the exact assemblies being compared. Provide the original reference and the proposed replacement reference, along with the full machine model and established model year.
- Request documented pinion information. Record tooth count and outside diameter separately. Ask for a drawing or reference-unit confirmation where gear details are missing; do not treat those two values as a complete gear specification.
- Compare the mounting arrangement. Confirm studs versus holes, threaded versus unthreaded features, hole diameters, spacing, housing location, and installation angle. Mark unpublished dimensions as unresolved.
- Resolve rotation and connection details. Confirm any conflicting rotation statements and compare terminal location, orientation, and applicable electrical specifications.
Label photographs by view, especially the drive end, mounting face, and terminal side. For measurements, record the units and the exact points or faces measured. A photograph documents what is visible, but it is not a scale drawing.
A useful supplier response should identify which dimensions and specifications have been confirmed and which remain unknown. A response that confirms only the number of teeth leaves the additional gear and mounting questions open.