Technical SBC running super rich

I have a freshly built SBC 350 with a single 600 cfm Edelbrock carburetor sitting on a tunnel ram intake. It has a comp cams RV grind with the timing gear set at '0'. The idle mixture is dialed in. The MSD electronic distributor has a vacuum advance with initial timing set at 8 deg. advanced. The electric choke works properly ( it's all the way open when warmed up).

Problem....the motor runs super super rich and lugs a bit going uphill. It has a wee bit of hesitation taking off from a stop light. I can probably adjust the accelerator pump linkage to address the hesitation but I need to figure out why it's running super super rich.

Suggestions anyone?

My avatar is the hotrod I'm refering to.

 

How did you determine that it's running rich?

And did you set the float levels on the carb before installing it?

What RPM going uphill, is it lugging at?

 

How do you know it is running rich?

 

@Lloyd's paint & glass you guy’s need to exchange notes.

 

How radical is your cam (duration LSA)?
With Eddy carbs part of the tuning process involves metering rods and jet changes.
(NOT just stick it on and adjust the mixture screws).
...............Especially with a single carb on a tunnel ram with an RV grind cam.!?!!...........
Ya need an Edelbrock tuning kit with different springs/metering rods/and jets( Summit has 'em & Advance etc)
ALSO.... tuning the ignition curve is a must. (MORE initial advance and a quicker advance curve....)
It isn't hard.....it just takes patience.
Go on line to how to tune my Edelbrock Carb.
Step by Step EZ to follow.
6sally6

 

Has to be the power valve?

 

The covers that are over the metering rod pistons loosen the screw a pivot the covers enough to see the piston then snug the screw start the engine and the pistons should be pulled all the way down at idle.

 

It sucks gas like a banshee and the exhaust pipes have loads of black soot.

 

Sounds like I need to back up a little bit. I need to make sure the metering rods a fully closed at idle and check the float level. Thanks for the reminder.

 

Also make sure your fuel pressure is 4.5-5.5 they do not like anything higher than that.

 

^^^^^ I’ve never opened an Edelbrock but have have to think the orifice at the needle and seat is larger because of the single inlet. If my hunch is true??? that would explain why Edelbrock carb needs lower pressure to seat valve correctly.

 

Hunchbusted!

Edelbrocks have one inlet but the two bowls are fed from two separate valves. There's an internal transfer tube that runs across the carb directly behind the inlet port.

Chris

 

Float buoyancy. Float arm leverage both determine how much pressure the needle valve will hold .

 

Oh shit, I didn't see that it's an edelbrock. Yeah, might have to change the springs on the metering rods to a lighter spring. At idle, loosen the small screws with the torx or a 1/4" socket, swing it open and see if the metering rods are sucked down. If they aren't, or if they're bouncing, fuel is dumping in through the jets.

 

Download Edelbrocks tuning guide. Study it . Make tuning adjustments, and check plugs. Tuning is process. A AFR gauge will help you . These carbs are very tunable and work very well with fuel metering. Float level and fuel PSI must be adjusted spot on.

 

No wonder to why these carbs are so w i d e.

 

Large runner huge plenum manifold, with a small cam, with attempted operation on the street.

This is a recipe for poor fuel atomization.

Raw fuel won't fire off like a properly atomized mixture.

 

I'm a Holley guy, never liked anything else outside of Q-Jets. How do the plugs look? Surprised this hasn't come up yet or I missed it.

 

Yea , I told him to check the plugs. Waiting patiently to hear back.

 

Plugs looked a little dark. I found the float level right on (7/16 w/ gasket installed). Fuel pressure is set at 3.5 psi. The metering rods, springs, and jets had been enlarged so I changed them back to factory original. Wiped out the chrome exhaust tips with solvent so I can keep a visual on soot buildup. I should have it back on the road this weekend so I'll run a tank of gas through it and check the plugs (E3) again.

 

My SBC inital timing is set @ 15 BTDC , total 35 10.5 91 pump gas'

 

E3 plugs are a joke gimmick. Put NGK plugs in it with the proper heat rang.

 

Seems to have worked. Plugs look better, no sooting in the exhaust tips. I'll leave it alone for a bit and see how it goes.