sounds like an air leak at carbs?

davids · Post by **davids** » Thu Mar 04, 2004 11:16 pm

Hey all, it sounds like I have a hissing sound or vacuum leak near my carbs. This started after I changed my fuel pump. Does the system need to be bled of any air, or is my logic unsound@?@?@?
Thanks for any help

Dave

oilleak · Post by **oilleak** » Fri Mar 05, 2004 10:12 am

Fuel pump has nothing to do with a vacuum leak. If you have any significant vacuum leak, the car will Idle high.

kt · Post by kt » Mon Mar 08, 2004 4:28 pm

why would it idle high?

if there's an air leak at the carbs, shouldn't it idle low?
...as there is more air than fuel.
if there's a vacuum leak in the system, shouldn't it also idle low?
...as the vacuum advance won't operate.

Marky510 · Post by **Marky510** » Tue Mar 09, 2004 12:43 am

The carbs themselves will hiss, pretty much normal. But some things to check. If you you have a stethescope, roam that around the carbs checking the throttle shafts and gaskets. If you hear the hissing around the shafts, try to move shafts back and forth while listening to see if he hissing changes, if so the shafts are worn and leaking. If you don't have a stethescope then a piece of vacuum hose should do, just stick it in your ear. If you don't hear any hissing other than at the air horns then it's pretty much normal.
One other thing to check is the vacuum fitting on the rear carb for the vacuum advance. My fitting had cracked slightly from being bent back and forth ( it finally broke which was fun to repair

)
If it's cracked slightly it could hiss/whistle. Just a few thoughts. Good luck.