This demonstration guide answers one field question about water left in the head through a freeze night. Measurements come before parts, and the notes are not a generic equipment FAQ.
Diagnose before replacing parts
Start with pump-saver fill versus a cracked head inspection. That reading separates water left in the head through a freeze night from adjacent faults that share the same complaint.
If the measurement is out of spec, treat the pump head as the primary path. If it is in spec, do not replace the pump head just to complete a parts list.
Repair the failed system
The usual correction is the pump head, installed to the documented spec for this complaint.
A demonstration shop records the finding so the next technician is not repeating a guess about water left in the head through a freeze night.
Stop before you make it worse
Do not blowing the pump out with a compressor and calling it done. That shortcut hides the original measurement and creates a second failure.
If the machine still fails after the pump head is corrected, convert the visit to a broader diagnosis rather than stacking parts.
Written and published by Ridgeline Small Engine.