Qft carb issue - Team Camaro Tech
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post #1 of 3 (permalink) Old Apr 14th, 13, 06:56 PM Thread Starter
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Qft carb issue

Hey guys

I have a new ss 750 double pumper with mechanical secondary on my new 383 stroker. Had the carb all dialed in and running great after initial running. Had to increase the squirter size from 31's to 35's to get rid of a little stumble on acceleration but other than that the carb is how it came from qft. Motor was run on Dyno when built by the builder with this carb. Combination makes tons of power and have a video of the dyno runs. All new msd ignition, bigger cam not much vacuum at idle, around 5 in. Timing set around 14 initial, running 94 octane. Was driving a couple weeks ago, pulled up to a light and the car just died. Started right back up but didn't want to idle and would hesitate when giving throttle then would finally catch and accelerate. Under open throttle the car ran fine so babied it home and was running like crap at any low rpm. Smelled really rich and would die if not on the throttle. Thinking it was a stuck needle and seat on the primaries, pulled the bowl off and pulled the needle and seat, blew out put back in. Was dumping fuel past the boosters at idle so base lined the mixture screws and reset them with the vacuum gauge. Have the car idling again, still smells a touch rich but overall not bad. Tried to test drive the car and it wants to die under initial acceleration in gear. Will hesitate and when catches then revs and accelerates fine. Will rev okay in park but not real crisp.

Floats are set right in the middle, fuel pressure at 6psi. Not sure what else to tell you? Could it be debris in one of the circuits in the carb? All new SS line, new mechanical Holley fuel pump, new russel fuel filter between the pump and carb. Scratching my head on this one. Haven't spent a lot of tuning time with Holley style carbs, mostly edelbrock and Rochester. Any suggestions and help would be great!
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post #2 of 3 (permalink) Old Apr 15th, 13, 04:16 AM
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Re: Qft carb issue

More than likely, if dribbling from th eventuris, then debris was in the needle & seat area.
If there, then morelikely elsewhere also.

Fuel level could be a little lower, not in the middle, but at the bottom of the hole/sight glass.
You also might remove and check the power valve ensuring its integrity and is generally, for starters, half of idle vacuum.

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post #3 of 3 (permalink) Old Apr 15th, 13, 07:10 AM Thread Starter
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Re: Qft carb issue

Thanks Everett I will be pulling the carb off and strip it completely to clean. Will also try the other things you have suggested. Appreciate the response.
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