Originally Posted by robert graham
The fuel cup on my 90HP Yamaha used to get pretty darn tight, but I started putting some silicon grease on the threads and O-ring and it helps a lot! When you re-install the cup, no reason to over-tighten it, just enough to compress that O-ring for a good seal. Good Luck!
On at least the F150, that cup with the O-ring, has to slide into the top black mount first
before you can tighten it down with "ring nut". Short of grinding down the outside of the cup just slightly (maybe .010") the cup WON'T go into the top mount, with or without the nut.... The new cup popped right in.
Had I not noticed just a very slight amount of fuel leakage (after an unexpected stall idleing out of a canal), I wouldn't have known there was a problem.. It had apparently been running that way for quite awhile...