Fuel starve, or something Options

[arsprod]

Teeners,

I swapped out the single carb that came with my 74 2.0 for new to me dual Weber 40's. It took a bit to get them jetted and adjusted but it's at least very close. The car runs great - and then it doesn't. With no consistency, it will start to stumble, cough, and backfire. Most of the time it works itself out though seems to be getting worse. I'm befuddled. (IMG:style_emoticons/default/confused24.gif)
Here's what I know:
- carbs are jetted main 145, air 200, idle 65, venturi 28
- plugs look ok, if anything rich
- I don't seem to have any vacuum leaks
- steady 3psi fuel pressure
- timing and valves adjusted
- new plugs

Help! thanks

Aaron

[VaccaRabite]

with 65 idles you are overjetted for a 2.0. At 3K you have both idles and mains pushing fuel to the engine. You may be fouling plugs. BTDT.

Zach

[arsprod]

with 65 idles you are overjetted for a 2.0. At 3K you have both idles and mains pushing fuel to the engine. You may be fouling plugs. BTDT.

Zach

Easy enough to try smaller idle jets. I'll actually test the plugs. You're saying that too much fuel going through the transition shows like too lean?

[Superhawk996]

with 65 idles you are overjetted for a 2.0. At 3K you have both idles and mains pushing fuel to the engine. You may be fouling plugs. BTDT.

Zach

Easy enough to try smaller idle jets. I'll actually test the plugs. You're saying that too much fuel going through the transition shows like too lean?

No, it would be rich misfire with the backfire coming from too much fuel being dumped in and it not lighting off until it gets dumped into the hot exhaust system.

This is why I’d like to see your plugs.