Yellow Tagged
The term are used for certified components.
Yellow tagged means used components that are deemed "serviceable" or "air worthy." It is sometimes called a return to service tag. It can mean that the components have been inspected and meet serviceable limits, repaired or overhauled. These components should come from a cerfitied repair station. The yellow tag will tell you what work has been accomplished, and generally what size the components have been repaired to (i.e. M003 on crankshaft main and rod journals, P10 on cylinders, etc.) Ask around about the shop that has done the component repair to verify the quality of their work. There are repair stations that we no longer accept work from due to poor quality repairs.
Red-tagged means these are reject parts considered unairworthy. On occasion, some engine shops and a lot of air boat builders use reject/red tagged parts in experimental applications. Some will say that although it's experimental and doesn't need to have certified parts, I would never put my family in an airplane built with a reject crank or cases. You have to ask yourself what risks you're willing to take.
There is also a repairable tag that repair stations use to identify parts that have been inspected and are considered eligible for repair with some work. It is generally a green tag.
Hope this information is helpful to you.
