Fiery the attached scan from a 1995 MEW article may help you devise a suitable venturi puller (the article was about reworking the early model Veco 19-which had a similar tight fitting venturi insert)-the dimensions for the MK-17 will be slightly different-but the principle is the same. In your position I'd go for heating rather than cooling-as heat will soften any oil residue that may be acting as a seal between the two surfaces........

ChrisM
'ffkiwi'