[Spridgets] Confused - Weber issues (longish)

[Lester]

Quick answer would lead me to believe that you are not on the idle  
circuit at all.

Changing main jet would NOT make any difference in idle IF you are  
using the idle circuit.

Old school way of adjusting idle:

	set idle with idle screw to proper revs

	adjust mixture screw until highest idle is achieved

	lower idle with idle screw

	REPEAT until ANY adjustment of mixture screw LOWERs revs.

(I know that you know this but other may not)

I would put money on the fact that you have caca in the idle circuit  
or that the idle jet is clogged.

Lester

.. of course I have only worked on DHSA and the like but Weber is  
fairly consistent..

On Jun 1, 2008, at 9:10 PM, Ron Soave wrote:

> I'm having issues with my Weber 45DCOE on a 1275
> (street car). The carb is mated to a 3.75" Minispares
> manifold, 36mm chokes. The below is a little
> convoluted, as things that should have mattered
> didn't, so I tried some unconventional things.
>
> I can't get it to idle properly, it wants to be too
> high. I "mixed" it as I usually do - set the idle
> speed screw 1/2 turn off the stop, used the mixture
> screws to set a smooth running idle, then adjusted RPM
> with the idle screw. I can't get the idle below 2200
> RPM without backfiring and spitting out the velocity
> stacks, even after finding the aux vent screw
> replaced. Timing is fine. Valves were fine. No
> discernible intake leaks. Replaced points, plugs,
> coil, wires, distributor with known good. Definitely
> all indications of lean. It runs great once it's off
> the progression circuit. So just for grins I upped the
> main size from 140 to 160 without changing the air
> corrector. It behaves better, I can drop the idle by
> 500 RPM, but still 500 shy of where I'd like it to be.
> The thing is...NONE OF THIS makes sense to me. I
> thought the mixture screws set the idle with a small
> contribution from the idle jet, and the idle jet
> progression circuit takes you from idle to about 2500
> RPM, where the main circuit kicks in. **Why did
> changing the main jet help at all?** And what will
> make it all better completely? When I get back from a
> drive, it reeks of gasoline and the plugs look rich. I
> only have the idle SPEED screw just barely cracked at
> this point, so I don't think I'm doing anything to the
> idle progression holes. I have only ever used F9 idle
> jets on 4 diffrent Weber setups I've had on my
> Sprites, so I don't have any other sizes "in stock". I
> tried that little venturi bypass thing, it didn't do
> anything.
>
> Any opinions are welcomed. Telling me to switch back
> to SUs is obvious so I respectfully ask that you
> refrain. I have never had much trouble dialing in a
> Weber before.
>
> Ron