Grose Jet question

["Ali Mohempour" <ali@ucla.edu>]

Hello all,
I'm trying to rebuild my first carburetor (ZS 150) on my '78 Spitfire, and I
wanna know what is this Grose Jet thing?  And if I install that (how?) do I
still need the needle?

Another thing:  The needle is covered by this yellow varnish, and I can't
get it off with the carb cleaner spray, what should I do? Thanks.

Ali

p.s.  The more I think about it, the more I realize what kind of mess I got
myself into by buying this little car last month.