TWIN-CHOKE CARBURETTOR PROBLEMS

1 Secondary throttle

On most twin-choke carbs, the secondary throttle barrel opens after the primary throttle is two thirds of the way or fully open. Make sure the secondary mechanism operates freely and easily.

2 Same old tricks

The principles are the same as basic carbs. The main barrel usually has idle, transition and main systems, plus enrichment and an accelerator pump. The secondary barrel just has transition and main.

3 Hesitation

Make sure the secondary barrel’s butterfly seals when closed, or weak running and flat-spots will result during normal driving. Check the secondary transition system if there’s a mid-range hesitation.