Black Smoke on deceleration

[boondocker]

Hi, I rebuilt my quadrajet (Cliff's HP kit), it's a '77 olds qjet and the car runs fantastic. I noticed when I rev the engine there's no black smoke, but when I let of the gas I get a puff of black smoke. I also noticed my plugs are black...seems real rich and I've tried adjusting my front mixture screws to no avail. Any ideas would be appreciated.

[Cliff Ruggles]

What are the engine specs, and how did you set the carb up for it?.....Cliff

[boondocker]

engine_info = '72 Oldsmobile 350R, Rebored .30 over (355), forged flat top
pistons
heads = 7A rebuilt, comp magnum pushrods, HE rockers
exhaust = Dual FlowMasters with Headman headers
intake = Stock
rear_ratio = 2.73 non-posi
carb_info = Qjet '77 olds carb_number = 17057252 APU
cam_specs = Comp XE-262 (olds)
.475/.480 lift, 218/224 @ 0.50, @110
purchased CR - HP carb kit with the following:
Electric choke (set at mid way)
Jets .073
Primary Metering Rods .043
Idle tubes .037
Natural Power Piston spring
CR choke pull off and link (didn't adjust)

[Cliff Ruggles]

Any other modifications to the idle system.  Lacking control of the idle fuel indicates either not enough idle fuel, or too much. 

Is there any "nozzle drip" from the boosters at idle speed?.....Cliff

[boondocker]

Thanks Cliff,
I didn't explain very well initially, the black smoke appears when i rev the engine and then let off, doesn't appear when idling...in fact the idling and overall performance of this engine is awesome...can't keep the tires from spinning.

[boondocker]

Just checked...No leaks, also, no modifications although I'm using an aftermarket breather assembly...I get smoke with or without the breather in place

[boondocker]

...could this be a timing issue?

[Cliff Ruggles]

Unlikely as the engine performs well.  Might not need all the accl pump shot you are getting.  Try moving the link to the outer hole in the arm......Cliff

[boondocker]

We'll I got a chance to move the pump lever to the end...and low and behold it fixed the problem!
No wonder they say your the "best in the business", thanks Cliff for the great setup!
Dave

[Cliff Ruggles]

Good news!...and thanks....Cliff