While installing the pushrod tube conversion kit on my '54 170, I happened to notice that the carb air box was rather loose. Further examination showed it was not the air box, but rather the entire float bowl assembly was just hanging from the main body of the carbureter One of the four screws had backed out 1/2 inch and the other were two/three turns loose...even with the locking tab assemblies in place Would not have been much longer before fuel would have really been spilling out of the carb and the float bowl dropping off the main body Is this a recurrent problem with the O-300 and would a better locking system for the four fasteners be to install drilled screws and then safety wire them all down
Are you certain your locking tabs were properly installed? The re-use of tabs, once removed, is not to be done, yet I've seen carbs to which that has been done. Once the tabs have been bent to hold the "flats" of the bolt-head, any re-bending of them just weakens them. The tab may later break and fall off, and even tho the remaining portion may look healthy, in actual fact there's nothing holding the bolt or preventing it's backing off.
The best thing I believe is to use new tabs during rebuild or repair.
One of the four screws had backed out 1/2 inch and the other were two/three turns loose...even with the locking tab assemblies in place 
Would not have been much longer before fuel would have really been spilling out of the carb and the float bowl dropping off the main body 
Is this a recurrent problem with the O-300 and would a better locking system for the four fasteners be to install drilled screws and then safety wire them all down 
