Thermoquad tuning on 318

The off idle stumble: you could have TWO problems.
[1] Just adding a little throttle to move the car
[2] When you stab the throttle.


[1] Remove the carb & check how much T slot is showing below the blades 0.020 - 0.040" is ideal. If NONE showing it indicates an air leak OR this carb has bypass air holes; these could be in the carb base, in the pri blades, or both. The symptom is a small flat spot because most of the t slot is above the blades & acts as an air leak, leaning the mixture. The fix is to plug the holes. If there are two sets of holes, plug one set & retest. Holes in the blades can be sealed with pop rivets [ may have to drill the holes to 1/8" ]. Holes in the base can be sealed with welding/coat hangar wire. Peen the alum top & bottom with a punch to hold in place.

[2] Large throttle opening/flat spot is leanness. Remove the met rods & test. This will add a lot more fuel.

[a] What is the carb model #? It is stamped on one of the mounting feet.
These carbs have a lot of internal passages/orifices that can be plugged with debris or get corrosion from sitting around. No way to really tell.
[c] Report back.