Bubbles
My 912s with 600 hours has been intermittently rough at 5000RPM. Removing the cowl I noticed small fuel bubbles coming up the float chamber vent tube. Removing the float bowl and the bowl was a little over 1/2 full and the floats were weighing about as a new one would. Removing the top and the diaphragm and circlip looks good. Any ideas on a bubbling vent line?