So I have to find out if the injector holes are all opened and not plugged on this late 60's Case 580 CK backhoe / loader D 188 motor . I Removed the injectors as it sat not running I think about 10 years in a barn or more and so looking at it I see at the top is 2 small nuts on a shaft so I removed it and tried to spray carb cleaner but nothing comes out the nozzle as is looks like its not a open passage to the tip and in both the supply line and also down inside the injector tube the manufacture has a design that is just not a open style ...Im sure it is desogned that way for a reason but you cant just look down inside it like a straw...so I have not been successful in blowing carb cleaner out the nozzle so far. At the nozzle end there is a white nylon o ring about 1/2 inch from the end and it appears that maybw the tip is screwed on and the shaft there is 2 different colors and so I want to try to unscrew it but might end up putting marks on the tube so I want to know if that nozzle screws off to clean it ? If it does not screw off then I might be trying to take something off that does not come off? So does that nozzle / end piece come off with the Plastic o-ring attached or not ? And also is the adjustment mechinism with the shaft and 2 nuts at the top something I can adjust or do I need to take it to someone wht has to do it on a bench test?