Voltage to auto choke disappearing under load

Hi, I have an odd issue where I can measure 11 volts across the plug for the auto choke when the unit is disconnected, but when I connect it the voltage disappears. I've tested the auto choke direct to the battery and it works fine.

There seems to be an issue on the ground side. The 'negative' wire (grey) goes to the CDI, and the CDI then has a separate wire to ground (blue).

With the auto choke connected, I can measure voltage between positive on the choke, and blue on the CDI, but not when I switch to grey on the CDI. And yes, there is continuity between grey at the CDI and auto choke ends.

If there's any electrical experts out there who can weigh in I'd be super grateful, cheers!