This demonstration guide answers one field question about lines that harden and leak air at the pickup. Measurements come before parts, and the notes are not a generic equipment FAQ.
Diagnose before replacing parts
Start with line durometer and air-leak spray test. That reading separates lines that harden and leak air at the pickup from adjacent faults that share the same complaint.
If the measurement is out of spec, treat the fuel lines and pickup filter as the primary path. If it is in spec, do not replace the fuel lines and pickup filter just to complete a parts list.
Repair the failed system
The usual correction is the fuel lines and pickup filter, installed to the documented spec for this complaint.
A demonstration shop records the finding so the next technician is not repeating a guess about lines that harden and leak air at the pickup.
Stop before you make it worse
Do not patching a line with electrical tape. That shortcut hides the original measurement and creates a second failure.
If the machine still fails after the fuel lines and pickup filter is corrected, convert the visit to a broader diagnosis rather than stacking parts.
Written and published by Ridgeline Small Engine.