a note on tanks some of the ones that come on the Hobbico ARF's are pretty week and as noted if the stopper is not tight enough or too tight blowing up the tank seal, you can get a leak mine did on my NEXTAR RTF filled my fuse with fuel only noticed it after a couple of dead sticks fuel, was running out the bottom I was bummed to say the least, sullivan tanks are a brand I like to use if I need to buy one. as for cleaning balsa denatured alcohol works well to break down the oil in the fueland evaporates quickly, it is also compatable with epoxy if you are going to seal your tank compartment you won't have any negative reactions, alcohol is also epoxy thinner and used for clean up FYI. if you dont seal the compartment just adds weight IMO wick some thin CA around the seams to make sure they havn't loosened up.
as for your spinner send it back to tower hobbies and most likely they will replace it free ,funny I have not had any problems with the plastic spinners I have but I use a elec. starter not to into the chicken stick
the motor mount and spinner I use on my 46AX is from a nextar( I got a extra one from tower) the engine mount and spinner was 12$ the rubber engine mounts separatly are 2.20.
I like alum spinners but use them for larger engines not for a 46 if you insist on getting one for your engine try Dave Brown products he has good prices