For reference: 3.8 E engine, modified head by Bill Terry circa 2002, 3x HD8 SU, UO needles.
Recently rebuilt my carburetors, old jets were frozen in place and diaphragms were shot.
First puzzle is that with the car fully warm, choke off it’s idling around 1000-1200rpm with the slow idle screws all the way in against their seats.
2nd puzzle is the manual says adjust the mixture screw until you get the highest rpm, and that if lifting the piston results in rpm drop it’s lean. Increasing the mixture (screw down) raises the rpm, and piston lift results in stumble indicating lean mixture.
However, removing the manifold vacuum hose (that goes to brake booster) results in higher rpm also, indicating rich mixture. Further, it started very easily this morning with no choke.
The high idle seems to indicate a vacuum/air leak. I have checked for tight connections, and have dripped some oil around possible sources (throttle shafts, etc) to no effect. Also tried the carb cleaner spray method around other areas, also to no effect.
Vacuum at rear manifold port (to booster) is a bit low ~13-15”. Vacuum at front port (to distributor) isn’t really measuring which seems odd…
Timing as about 10d BTDC @1,000rpm
Obviously I’m missing something… but what?