i have a buddy with an ea81, who failed emission(in washington) He had way too much carbon monoxide %. I believe this is the unburnt fuel measurement. Is this fixable and if so, how? thanks

CO is a byproduct of a rich mixture. HC is unburned fuel. sometimes go hand in hand if problem is bad enough.

 

basically its too rich for some reason. do all the usual tune up checks first. then try to narrow down the cause.