Secondary throttle problem on Weber 500 (1404) carb

jefferybond · Post by **jefferybond** » Fri Dec 08, 2006 1:38 pm

Hi folks,

I've got a Weber/Edelbrock 1404 four barrel carb on my 3.5, and it goes very well apart from one minor annoyance:

The secondary throttle plates are a bit reluctant to close off properly at idle, leading to a slightly fast and rough idle. If I manually force them shut by fiddling with the lever, the idle comes back to normal. It's rather strange, because when the engine is off, the secondary throttles snap shut cleanly with the return spring, but when the engine is idling, there seems to be some stiffness there, causing the problem (maybe because of manifold vacuum sucking on the plates).

The carb was new 4000 miles ago, BTW.

Any ideas?

Jeff

Alley Kat · Post by **Alley Kat** » Fri Dec 08, 2006 1:56 pm

Soggy springs? Or not enough tension? Happened to me before.

jefferybond · Post by **jefferybond** » Fri Dec 08, 2006 2:04 pm

Alley Kat wrote:Soggy springs? Or not enough tension? Happened to me before.

Well the return spring on the secondaries is a weedy looking thing compared to the primaries, but the carb is nearly new.

How did you fix it? Did you just wind a few more turns on the existing spring, or fit a bigger one?

Cheers,
Jeff

Alley Kat · Post by **Alley Kat** » Fri Dec 08, 2006 2:08 pm

Hi Jeff
I had to swap out a spring 'cos it was just too weedy; put in another one, which needed a bit of playing/experimenting with angle & distance (to close the throttle and give a nice pedal feel, not too stiff),
cheers
Bill

Alley Kat · Post by **Alley Kat** » Fri Dec 08, 2006 3:04 pm

PS - worth lubricating the throttle cable too maybe, p'raps it's hanging up a little too, if the spring pull is a bit weak.