new 750 speed demon rich idle

[keng]

Just bought a speed demon 750 .Have a rich idle I just can't seem to lean out.Mixture screws are 1/4 turn out from bottom,I can stall the car if I try and turn them in.Raw unburnt smell in the exhaust,plugs black to brown.Plugs were new fresh oil change wasted.
Throttle are only showing maybe .020 of the transfer slots.
I'm lost.I'm looking for that well burnt exhaust ordor not a that heavy rich smell.Is this possible.

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67 cuda 3500w/me - 383 stock bore9.6to1CR, - stock 906's 2.14in 1.81ex ported for the valves,MP.474 cam - ,MP M1 single plane - , Holley 750 DP 72's and 76's, 4.5 power valve 35 squiters pri. and sec. - ,Autolite 75's, - ram air - ,Griffin radiator - ,CPPA 1 3/4 headers - ,strip flowmasters 3" - ,MP electronic conversion 38* total in at 1800rpm - ,BM holeshot 3000 converter - , comp rebuild 727 - ,BM super cooler - BM Hammer shifter - ,430 gears with a Detriot Locker - , BF Goodrich drag radials 27.5 dia. 275-60-15's tires , MP drag shocks, slant six torsion bars,super stock springs clamped fronts no clamps rear,,pinion snubber set tight, 5* pinion angle,,comp engineering adjust front shocks set at 90/10 - best to date0 12.74 @ 105mph

[Gam Man]

Yeah I know what you mean..... I have the same prob with a brand new 830 annular Holley comp series that i just fitted. I normally am pretty good at setting up these carbs, but i just cant figger out why this is running rich at idle.

Power valves fitted are 4.5" Hg and worked real well in my 780 vac sec, with clean plugs and no unburnt fuels.

Any one else have some hints ?

[cuda66273]

There are several things that cause a rich idle condition and *keng* and I are working off the board to find his solution, we'll post what we find when we get it fixed.

But, here's a few things to check:

1. Not enough initial timing

Solution: Adjust your timing at idle with a tach to get the most RPM then go back and start your four adjustment procedure. CHECK MAX TIMING BEFORE YOU DRIVE THE CAR, a distributor that is not curved correctly can cause catastrophic engine damage if you attempt to run it with the timing too far advanced.

2. Fuel dripping from boosters

Solution: lower the float level until the dripping stops. NOTE: Fuel should still be visable in the site glass, once you get it all dial in you can raise the float level back to the lower or center mark.

3. Transition slot exposed to far

Solution: reset the butterflies to Zero

4. Power valve to low

Solution: check vacuum at idle in gear and install a power valve 1 to 1.5 below your idle Vacuum.

5. Open valve causing excessive low vacuum.

Solution: adjust valves correctly.

6. Bowl bolts not tight or overtight causing a leak between the bowl/metering blocks and the center section.

Solution: remove float bowls intall all new gaskets and retork to spec.

7. Excessive fuel pressure

Solution: Install pressure regulator and Fuel Pressure gauge, set to 6.5 to 7 lbs.

8. Idle speed screws set incorrectly allowing the carb to start opening the primary throttle circuits.

Solution: reset the screws to zero and turn in 1/4 turn and start 4 corner adjustment again.

9. Just can't make it work???

Solution: Send it to me I'll check it out, install it on the Cuda and dial it real close for you, then walk you through the final tuning on your car via phone. This will cost you frieght both directions the labor and parts if it should by some chance need something are free for you guy's.

Sorry this applies to Demon's only...this does not include parts that have been damaged by dropping the carb or incorrect installation.

If you want me to try and solve your Holley problems my shop rate is $35.00 an hour for you Guy's ($55 for anyone else) If I can't fix it there's no charge to check it out.

[cuda66273]

Gam Man...I just noticed...did you mean to say "Power Valve"S"?????????????

You should only run a power valve in the primary metering block, the secondary block should have a block off, unless your dirt track racing?

The power valve does not affect the idle setting.