so close.. 2.0 weber 44s drives and misses Options

[gotxqss]

So did some searching.. Did some reading.. Have had this car for awhile and finally got off the ass to start tinkerin!

Cars a 75 with a 2.0 from another car.. Could be stock could be rebuilt I have no clue.. Guessing its a stock or mildly touched motor.. I had a buddy come over and get it idling pretty good.

Set float levels
Cleaned and put back together
Set linkage that sorta stuff

Just a quik list of the main parts as there might be a section that's just flatout needs attention .

Weber 44idf
32 venturi
175 air (I think these need to be higher?)
55 idles
F11 et
140 main

So anyway hopefully 1 of those things will standout to try to get me closer..

Haven't driven the car alll that much but from what I have. It will idle and rev well, the super low speed low rpm stuff feels decent but the midrange has stumbles. At a steady cruise it will pop as well. If I get in the gas pretty hard down low(under 2500rpm) it will be pretty dead till about 4k and then pulls really well to 6k.

So of course something is off but I don't have a weber guru here in vegas that I know of that can just handle it so now im asking for help..

Maybe there are some things that im missing to get me closer..

I do have 50 idles and 135 mains laying around..

Thanks guys.. Ill keep up and get this handled!!!!!!

[jmill]

Thanks, I don't know how smart I am but I'll tell you what I know.

I wish I had more info on all the E/Ts but I've only had experience with 2. The F11 and the F7. They are the only 2 that were readily available to me. They are also night and day apart. I can give specifics for the F7 and F11 and since they are so different you can understand how they all work.

As air passes through the carb it pulls air and fuel from the fuel wells. I don't want to get crazy with the venturi principle and D/P but as velocity increases pressure decreases. The faster the air flows through the carb the more fuel and air it pulls from the fuel wells due to differential pressure. (Thats why big vents on little engines don't work so well. You don't get adequate DP). The mains and A/C jets control amounts. The E/T controls how the air and fuel are mixed.

F7 = Small outside diameter which leaves lots of room for fuel in the fuel well. It has holes placed low on the tube. Air pulled from the A/C jet has to pass through a majority of fuel in the fuel well before it's pulled into the venturi. This design leads to great off the line fuel availability and a richer transition. It's more sensitive to fuel level changes in the fuel well and float bowl. Larger A/C jets need to be used to avoid high velocity enrichment.

F11 = The E/T itself has a large diameter and it leaves less space in the fuel well for fuel. The E/T also has holes placed high on the tube. Air pulled from the A/C jet passes through minimal fuel in the fuel well. This design leads to leaner transitions and less fuel available in the fuel wells when you stomp on it. It is also less sensitive to fuel level changes in the fuel well and float bowl. A/C jets above 2.00 lean up the high velocity mixture.

The diameter of the tube determines the amount of fuel available in the fuel wells and how sensitive it is to fuel level changes.

The hole placement determines where in the fuel well the air is mixed with the fuel. Low = richer, high = leaner.

I would assume more and smaller holes would provide better emulsion. I only got into where they where placed.