It sounds like you have Van's regular gascolator and yes, the bowl of the gascolator turns. In fact the whole bowl comes off (and needs to come off) to check the screen. That's what the four screws are for, to hold the bowl tightly up into the rest of the gascolator, but the bowl will still probably turn if wrenched on hard enough. Sounds like maybe you haven't checked your gascolator screen yet, so that should be something you look into. Hope this helps.
RV-9 Flying, 0-320, Catto
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