How Aftermarket Coils Fail Air-Gap and Connector Specs

A demonstration field guide for a coil whose laminations do not match the flywheel radius using lamination radius versus flywheel before replacing the coil.

This demonstration guide answers one field question about a coil whose laminations do not match the flywheel radius. Measurements come before parts, and the notes are not a generic equipment FAQ.

Diagnose before replacing parts

Start with lamination radius versus flywheel. That reading separates a coil whose laminations do not match the flywheel radius from adjacent faults that share the same complaint.

If the measurement is out of spec, treat the coil as the primary path. If it is in spec, do not replace the coil just to complete a parts list.

Repair the failed system

The usual correction is the coil, installed to the documented spec for this complaint.

A demonstration shop records the finding so the next technician is not repeating a guess about a coil whose laminations do not match the flywheel radius.

Stop before you make it worse

Do not filing laminations to "make it fit". That shortcut hides the original measurement and creates a second failure.

If the machine still fails after the coil is corrected, convert the visit to a broader diagnosis rather than stacking parts.

Written and published by Ridgeline Small Engine.

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