In an earlier service I noticed I didn’t have a main/large gasket to stop water leaks coming out the edges of the bottom end – so I used gasket sealer (the red stuff you see all along the end of the mating surfaces). I still don’t know if there is supposed to be a gasket here (I doubt it) but because there isn’t much pressure at this point it is fine to use some gasket maker/sealer. Just make sure it is resistant to heat and salt water. Using sand paper remove any old sealant (im using Wet&Dry 320. It takes longer to clean it up at least I won’t damage the surface).