1.9 8v with stage 3 head, 4 branch, twin weber 45's car recently rebuilt, including reinstalling carbs, throttle linkage etc. when i change gear, the revs stay where they are and sometimes increase. if i let the gearing bring the revs down, and downshift, revs stay where they are. I've checked the linkage and can't feel anything sticking and full range of motion is possible. externally all seems to be working correctly. similarly on the manual choke, all appears to moving through range, and externally moving as designed. but if feels as if something is stuck, holding the revs when i change gear. anyone got any help? is it posiible that while everything appears to not be stuck externally, there is something internal to the carbs stuck or sticking??
May be the throttle shaft bearings had that wrong with my Dellortos you know the long rod that controls the butterflies? You will need to remove the carbs and use the arms the linkage connects to, to see if the butterflies open and close smoothly. If not then you'll need new shafts and bearings. May also be worth stripping and sonic cleaning but it doesn't sound like a blockage.
There is an internal return spring behind a plate on the face of the carb that mounts to the inlet manifold. The plate is held on with 2 screws and the spring locates behind that. They can break occasionally and cause problems. You should be able to see if the throttle shafts return properly on each carb though without taking them off. If the carbs have been off the inlet manifold they may need to be balanced again or the o ring plates may have settled slightly causing an air leak and the increased revs. Best to get it checked out as a sticking throttle is not good.
