Modern Vespa

Hello all
Hopefully a simple answered question….
Spaco carb….I assume the spring on the slider should be strong enough to
Pull the slider back to its resting closed/idle position ? Mine currently isn't when connected up to the throttle cable.
I've got a problem when I pull the clutch in when changing up, the revs stay high. Do the same with no throttle (like going downhill) and she idles fine. I'm certain there's no seal gone or air leak because I can do a 40 mile trip problem free. Just had the carb serviced too hoping it was just in need of new gaskets. No changes…this has just developed?
Kevin

Loosen the cable adjuster nut at the front of the carb box the cable goes through.

I've had this happen where the adjuster nut was holding the throttle cable too tight so the throttle slide wouldn't return completely.. leaving the idle to remain high no matter what adjustment you make on the carb itself.

Aside from that, of it's auto lube carb.. grease the auto lube spring.

If not that, then your carb might be warped and the slide gets stuck when retracting. New carb and don't tighten one holding bolt more than the other. Slowly tighten them back and forth equally till torqued down appropriately.

I'm going to wager an crusty throttle cable is partly to blame as well.

Thanks men for the reply….it's non auto lube by the way…
I have the original dellorto carb and noticed the spring seems way superior to the one I have so I'm going to swap that first…will let you know