I meant for the "brass fitting with the brass winged plug or the blue plastic one" I've not seen any of these in all of my searches that I'm sure that would fit.
The bushing Merc uses with the Blue plastic plugs is 22-860088
The Blue plastic plug and O ring is 22-8M0119211
The plastic ones do break it they are tightened to tight, and they also need to be replaced every so often. Hardin Marine makes some plugs that are all stainless steel
