/6 Weber Carb Questions -> Jets, Who said you can never be too rich? Options

[Carl]

I'm trying to lean out a car that goes through gas like a drunken sailor. To start the process, I want to convert the carbs back to the original factory jetting then address the performance issues if that setting is too lean. Hopefully, there are authorities on carbs out there that know the answers to the following questions:

/6's came with Weber 40IDT3C's, as did the 911T (same engine). The /6 factory manual says the jetting should be:
45 idle jets
105 mains
170 air jets
F1 emulsion tubes

The Pat Braden book on Weber's has the following jetting for 40IDT3C's for the 911T:
50 idles
110 mains
185 airs
F2 emulsion tubes

Which is correct factory jetting for the 914/6?

There are different jetting arrangements for 40IDA3C's. Braden says the IDA's were on the 911L engine. Were they used on other P engines?

There are more references to IDA's in the printed material than IDT's. This doesn't make sense to me if they only came on 911L's because there weren't a lot of them produced vs the 911T's.

What are the differences between the IDA's and IDT's? The external appearance is the same but the jetting is different for engines of the same displacement.

The engine in my car has a 911T crank and case with a 2L 911E pistons, cyls & cams. The 911E was an MFI engine. I've been told there are differences between cams for MFI engines vs carbs. Is this true? If so, how are they different? Should my engine be jetted differently because of it?

and finally, how come a dropped nut will always land in a location that's the most difficult to see, reach, or both? (IMG:style_emoticons/default/idea.gif)

Thanks for the help.

[krk]

Jeff: iirc = if I recall correctly

Thanks, Kim. I ran through my entire inventory of Weber knowledge that day we tried to tune yours. Not too successfully, iirc (there it is again, Jeff). You've since gone on to greater heights in Weberdom so now I can only hope to pick up some fragments from you.

Some questions related to all this:
A while ago I got recommendations for Webers on an E engine and that's the way my carbs were set. 55 idles, 125 mains, 180 airs and F1 tubes. This is just way too rich. Gas mileage sucks, the plugs are quite dark and the exhaust smells gassy. I don't know why this setup would be desirable.

I've not had the car on an analyzer for fear of pegging the meter and thought I'd fall back to original specs and experiment.

Thus the questions. Where to start?

Now you're pulling my leg!

The first set of carbs were so leaky around the shafts that we were doomed before we started.

But you do have a good question -- what should you set for the starting point. (do the dizzy check before of course)

Idles/Mains are certainly easy to swap in and out. We just need a few sizes to play with. We should just gather our inventory of the stuff we have together and figure out what to bring and what you would like to try.

F-tubes are of course harder and probably not practical -- it'd be easier to swap carbs on and off -- hm.. did you mention the venturi sizes? Those are also not so easy to "swap".....

kim.