This demonstration guide answers one field question about a set run near an open garage door. Measurements come before parts, and the notes are not a generic equipment FAQ.
Diagnose before replacing parts
Start with placement distance from openings. That reading separates a set run near an open garage door from adjacent faults that share the same complaint.
If the measurement is out of spec, treat the exhaust direction as the primary path. If it is in spec, do not replace the exhaust direction just to complete a parts list.
Repair the failed system
The usual correction is the exhaust direction, 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 set run near an open garage door.
Stop before you make it worse
Do not using a CO detector as permission to run indoors. That shortcut hides the original measurement and creates a second failure.
If the machine still fails after the exhaust direction is corrected, convert the visit to a broader diagnosis rather than stacking parts.
Written and published by Ridgeline Small Engine.