Too Rich

I've got a 235 chevy in a 49 chevy, I recently put dual carter/weber
carbs on it. It runs pretty good but it is very rich (plugs are black).
I set the fuel mixture on the lean side but it made no change.
Any of you guys have any thoughts on it?
Thanks
Jim

 

I once ran two fours, on a street prepped small block Chev.
Since the AFB's were off of Pontiacs(?) they simply flowed too much air.
Niagra Falls in the manifold. Washing cylinder walls of oil and that sort of thing.
Compare notes here on the HAMB, w/guys who know their cfm ratings, you may be able to lean them out enough.

 

I did another propane vacuum test today, and I found a vacuum leak at
the carb base. I'm going to fix that leak and try it again.

 

How did you go about leaning out the fuel mixture? Did you move the choke adjustment from a richer to a leaner setting? Did you turn the idle mixture screws in? Did you change the main metering jets? Did you change the float level?

 

I adjusted the fuel mixture screw. Before I go any deeper I am going to fix the carb base
leak. I don't really know a lot about these Carter/Weber carbs, but I have a feeling
I'm going to learn.

 

lol some of the guys on here will school ya!

 

What carb model(s) are they? Pics?

 

A vacuum leak in the base gasket will defiantly cause a too rich mixture. Check the gasket and re torque. Then re torque again.

But the next question is, are these two 4bbls on a 235 straight 6? Unless the motor has been drastically reworked that is WAY too much carb. I ran one weber/Carter/edelbrock on a 225 slant six and that thing took a lot of reworking to get it anywhere near right.-dd

Posted using the Full Custom H.A.M.B. App!

 

I'm going to assume you've just adjusted the idle mixture screw. If the car is running, but too rich going down the road, the idle mixture isn't really going have much effect on the problem.

If it's truly running too rich you should probably start with the basics. Check your fuel pressure. Check the float levels. Make sure the choke, if so equipped, is fully open after the engine is warmed up. Check your timing and manifold vacuum. With the engine idling look down into the carbs and see if there's fuel dripping from the main nozzles. It could be something fairly simple that's making it run rich.

 

Hi ChevyJim
I bought 2 carter/webers for my bucket build,using a 230 chevy inline 6,
do you have pics,of your linkage,and fuel line setup
Thanks in advance..

 

They are Carter/ Weber 2 barrels. They were originally used on
small engines like Ford Escorts, Vegas etc.

 

That's what I have, got them from the Stove bolt guy in Mi

 

What intake do you have?
I will post some pictures as soon as I can.

 

Choke not opening all the way or float level high, possible saturated floats.

 

running an offy intake

 

With the carbs facing the way they are, how are you going to set up your linkage?

 

here's more pics up close

 

Seems to me a leaky base gasket would cause a
lean condition, not rich.

 

Too much carb for the 235. Some guys like to run the small 216 carbs when running multi carbs on a 235.

 

cut down on the main jets... you could drive it pretty good with a 600 cfm 4 bbl carb...but its rarely gonna make opening on the second ports.... . Check your fuel/air mixture with a CO2 sensor/meter, and do the necessary adjust/modifications needed. Either way you got bigger venturies on this to carbs than the original one, so you gonna loose some torque in acceleration.