This demonstration guide answers one field question about a tank that runs dry while the engine still runs. Measurements come before parts, and the notes are not a generic equipment FAQ.
Diagnose before replacing parts
Start with float-valve shutoff and inlet vacuum. That reading separates a tank that runs dry while the engine still runs from adjacent faults that share the same complaint.
If the measurement is out of spec, treat the float valve as the primary path. If it is in spec, do not replace the float valve just to complete a parts list.
Repair the failed system
The usual correction is the float valve, 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 tank that runs dry while the engine still runs.
Stop before you make it worse
Do not bypassing the float to keep washing. That shortcut hides the original measurement and creates a second failure.
If the machine still fails after the float valve is corrected, convert the visit to a broader diagnosis rather than stacking parts.
Written and published by Ridgeline Small Engine.