This demonstration guide answers one field question about a tester that shows spark without holding a plug. Measurements come before parts, and the notes are not a generic equipment FAQ.
Diagnose before replacing parts
Start with tester gap versus a known-good spark. That reading separates a tester that shows spark without holding a plug from adjacent faults that share the same complaint.
If the measurement is out of spec, treat the tester lead as the primary path. If it is in spec, do not replace the tester lead just to complete a parts list.
Repair the failed system
The usual correction is the tester lead, 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 tester that shows spark without holding a plug.
Stop before you make it worse
Do not holding the plug boot in a wet hand. That shortcut hides the original measurement and creates a second failure.
If the machine still fails after the tester lead is corrected, convert the visit to a broader diagnosis rather than stacking parts.
Written and published by Ridgeline Small Engine.