This demonstration guide answers one field question about a volute that cannot contain the impeller. Measurements come before parts, and the notes are not a generic equipment FAQ.
Diagnose before replacing parts
Start with crack through the scroll. That reading separates a volute that cannot contain the impeller from adjacent faults that share the same complaint.
If the measurement is out of spec, treat the volute as the primary path. If it is in spec, do not replace the volute just to complete a parts list.
Repair the failed system
The usual correction is the volute, 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 volute that cannot contain the impeller.
Stop before you make it worse
Do not wrapping a volute in tape for one more weekend. That shortcut hides the original measurement and creates a second failure.
If the machine still fails after the volute is corrected, convert the visit to a broader diagnosis rather than stacking parts.
Written and published by Ridgeline Small Engine.