Weber 44 running rich Options

[Dave97]

2270 with Weber 44 is running rich
50 idle. 1 1/4 screw out
Had 55. Drives better, but the a/f stayed about the same
135 main
175 air
Floats set at 9 with gasket
Have wideband sensor
11.0 at idle
Light throttle might see 12.8
Decel 13.2
Full throttle 13.7
Is there a air by pass circuit? It's almost the opposite of a air leak
Thanks for your help

[McMark]

Hi Mark. All thru the rev range it is in the 11's. on level ground 4th gear 2400 rpm light throttle might see 12.5. Most driving under 3000 is in the 11's. full throttle at 5000 I'll see 13.2. Head temp most of the time is 200 Thank for your help. Is there a air bypass? It's almost the reverse of a air leak. Dave

I think you have a lot of different issues going on. This is pretty normal for carbs, mostly because people underestimate carb setup and tuning (IMHO). Here's an overview of what needs to be perfected before you start evaluating the carb setup. These need to be done in order.

If you skip, or don't understand any of these steps, you may end up wasting time chasing your tail. Take the time to ensure all of these are 100% correct. And ask for help/clarification on any of the steps. Being thorough here will ensure you have the best running carbs you can.

1. Check compression
2. Check for cold start valves - SOME Weber IDF style carbs have a lever system on the side that allows for extra fuel to be added. Even if your carbs don't have the lever installed, they MAY still have the plunger valves and those can stick or leak. If you're not sure on this, you must post pictures of your carbs so we can see for you.
3. Adjust valves - Make sure you know if you have stock pushrods, hydraulic lifters, or ChroMoly pushrods. Each have a different setting, and any of the three setups could be in you motor if you don't know the history.
4. Set ignition timing - Make sure points/condenser (or Pertonix), spark plug wires, cap, rotor, spark plugs are all in good condition.
5. Check float heights - This can be tricky, make sure that you're doing this correctly. Don't compress the ball spring while checking. Ideally double check the fuel level with the carbs assembled and the fuel pump running, by removing the main jet stack and looking into the hole. Measuring that way is more challenging, but more accurate.
6. Make sure you have the correct linkage - If you have a hex- or cross-bar linkage, get the CSP Bellcrank linkage before moving any farther.
7. Sync the carbs - Make sure to check airflow at idle AND off idle. Make sure your linkage reads equal airflows at two throttle positions, closed (idle) and slightly open (off-idle).
8. Check for fuel intrusion - Look down the carb throats while it's idling. There shouldn't be fuel droplets dripping onto the closed throttle plates. Occasional drips aren't uncommon (1 drip per minute or less). But regular drips or 'excessive' wetness on the closed throttle plate is a symptom of an issue.
9. Tune idle mixture - Use the mixture screws to adjust idle mixture. Most engines like to idle in the 12.5 AFR range.
10. Check driving mixtures - When checking these mixtures, try to maintain constant throttle position. Also pay attention to how the car performs with quick, snap throttle changes compared to slow even throttle opening. Varying the throttle position too much will engage the squirters and add extra fuel -- this complicates your tuning because you're constantly changing the amount of fuel and 'masking' the fuel coming from the jets.

A couple potentially helpful videos from my collection:

Here's an engine setup video I made a few weeks ago. The part about carb setup is obviously why I'm linking it here.

https://www.youtube.com/watch?v=ZS3oNSwkUPk


And here's a video of what's happening in the carb throat while driving. This gives you a bit of perspective of what an idling carbs looks like (no wetness, drips) and also what I'm talking about with throttle position changes and accel squirters.

https://www.youtube.com/watch?v=XYDmTkNTk3w