I agree with mojo. Fairly common 'issue' across the board with CC's. Check that PTO wiring! Pull back the protective sleeve on the PTO wiring as well to check for rubbing/breaks. You could also have a fuel pump issue (check for fuel in the filter after she quits), or you could have a plugged fuel cap vent. Loosen the gas cap after she quits & listen for a 'whoosh'. Like the other gents said, could be a coil heating up, expanding with an internal break.
G/luck
Joel