E4ME measurements any thoughts?

[Peer81]

Hello everybody,

Having my carb apart to change epoxy to seal the primairies I also took the time to measure some stuff.
It's a CCC controlled Q-jet with some minor alterations to the idle system.
What did I find:

Idle Tubes: 0.0315" (resized a second pair I have to 0.0345")
Idle down channel: 0.0465"
Upper idle air bleeds: 0.031" (in main body)
Lower idle air bleeds: 0.074"
Idle bypass air: 0.106"
Mixture screw holes:  resized to 0.0855"
Holes in plates: None

I see I also need to measure some other things but I'll to that next time.
Comparing this to Cliff's recipes I see two things.

1. My upper air bleeds are way smaller then in Cliff's 1st recipe (0.067")
2. My idle bypass air is much bigger then in Cliff's 1st recipe (0.080")

When the carb was on the engine it was alway's idling lean, no matter what I did with the mixture screw's. Last time after resizing the mixture screw holes it was still on the lean side but not that much. Anybody with thoughts on this one or idea's? Not that I want to change anything after testing but the different measurements strike me.

Greetings Peter

[Cliff Ruggles]

Have you installed new "O" rings on the upper idle airbleed adjustment?

The upper idle airbleed adjustment has a MAJOR impact on idle fuel delivery as well.  I'd try adjusting it to help add some fuel to the idle system, before doing any further modifications elsewhere.....Cliff

[Peer81]

Hello Cliff,

Could you explain to me about the "O" rings in relation to the upper idle air bleeds? I don't understand what your saying. I didn't alter my upper idle air bleeds just measured them.

Greetings Peter

[omaha]

  IIRC, some of those carbs have an airbleed "ADJUSTMENT". Its on top of the main casting towards the front of the venturi's opening. Looke for the triangle. Under it is the single adjustment. (feeds both airbleeds) It's like a littler needle adjustment. It has an O-ring to seal it. Ive never actually seen one before in person, only in some pictures of them. haha. if the O ring was missing or deteriorated, this would greatky effect the idls mix.      ( kind of a neat deal though if you could adapt it to carbs that dont have it.)

[Peer81]

Thank you for the explination. I was thinking in another direction but now I understand the relation between the upper idle air bleeds and the rubber o-rings from the needle.
If I remember correctly I installed new o-rings on the first rebuild, but I'll check for the condition of the rings.


Greetings Peter