As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKE OFF CREW HAD A FUEL ODOR INSIDE COCKPIT. AIRCRAFT TURN AROUND AND FOUND FUEL CAP NOT INSTALLED PROPERLY BY FBO. IAW GOM 9.4, AIRCRAFT PREFLIGHT WALK-AROUND, COWLS, CAPS AND FASTENERS SHOULD BE CHECKED FOR PROPER INSTALLATION BEFORE FLIGHT