Does the fuel screw turn very hard or is it just me? I have turned it about one turn
and it is very difficult to turn, yes I have removed the collar, don't want to break it
so I quit. 92 W350 LE regular cab, 4" exhaust, BHAF, fuel pin turned, 3200K Spring, 64,000 original miles 2nd owner (father in law bought it new) Mint, and I mean "Mint" condition, I'll get couple of pics on here soon.
Thanks All

 

shouldnt be that hard to turn as long as you have the jam nut backed off

 

maybe a little piece of metal from where the colar wat tacked on is still on there and binding up the threads.

 

Thanks for quick replies, I will pull it out and check threads

 

If you have the tools try chasing the threads.