This demonstration guide answers one field question about timing shift after a blade strike. Measurements come before parts, and the notes are not a generic equipment FAQ.
Diagnose before replacing parts
Start with timing-mark alignment at TDC. That reading separates timing shift after a blade strike from adjacent faults that share the same complaint.
If the measurement is out of spec, treat the flywheel key as the primary path. If it is in spec, do not replace the flywheel key just to complete a parts list.
Repair the failed system
The usual correction is the flywheel key, installed to the documented spec for this complaint.
A demonstration shop records the finding so the next technician is not repeating a guess about timing shift after a blade strike.
Stop before you make it worse
Do not reusing a partially sheared key because it "still fits". That shortcut hides the original measurement and creates a second failure.
If the machine still fails after the flywheel key is corrected, convert the visit to a broader diagnosis rather than stacking parts.
Written and published by Ridgeline Small Engine.