Author Topic: Holley carb Question  (Read 3451 times)

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Offline turbota400

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Holley carb Question
« on: April 13, 2007, 11:51:19 PM »
I'm having a problem with my Holley carb (750 CFM vac. secondary) that I've never seem before.  I just replaced the vacuum booster on my truck because it had a bad vac. leak and then I swapped my Edelbrock Carb out for my Holley.  When I tried to start it, it wouldn't start unless the throttle was to the floor which made me think it might be flooded.  I let it sit for about an hour and tried again with the same results.  Once it started, it ran fairly rough for a few seconds then seemed to "catch up" and when I let off, it died immediatly like I turned the key off.  Tried again and if I held the throttle about halfway open after it started, it would run rough at about 1000 RPM.  It won't even try to start unless it is all the way to the floor.  It starts fine with the Edelbrock, but runs poorly.  Its an old carb.

I checked for vac. leaks and found none.  I just rebuilt the carb (Holley).  Float level is set to spec.  Idle screws are 1 1/2 turns out.  Accelerator pump is new.  Power valve is new with blowout protection. 

Any ideas?   ??? ???
Shawn
1972 Chevy C-10
1980 Trans Am Pace Car - 428 ci Poncho in the works
1992 S-10 2WD- Work Bomber/Gas saver
1997 Chevy X-cab 4x4 - Vortec 350

Offline chitownTA

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Re: Holley carb Question
« Reply #1 on: April 14, 2007, 01:56:18 AM »
timing could be off?

also check inside the carb to see if there's gas pooling.  I had a problem with my holley last year where the secondaries would just pour out gas for no reason and make it real hard to keep running unless i gave it throttle until I emptied the carb out and it would be fine for a few more days.  Havent figured it out since my trans crapped out last year.
« Last Edit: April 14, 2007, 01:59:07 AM by chitownTA »

Offline turbota400

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Re: Holley carb Question
« Reply #2 on: April 14, 2007, 09:43:38 PM »
timing is set at 6 degrees BTDC initial.  No pooling. 
Shawn
1972 Chevy C-10
1980 Trans Am Pace Car - 428 ci Poncho in the works
1992 S-10 2WD- Work Bomber/Gas saver
1997 Chevy X-cab 4x4 - Vortec 350

Offline Joker (§ir£Ğragon)

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Re: Holley carb Question
« Reply #3 on: April 14, 2007, 09:52:01 PM »
What about the secondary vac. canister spring? Could it be weak/broken allowing the secondaries to open slightly?

That's the one thing I never liked about the 3310 and other Holley vac. secondary carbs.
Larry


Offline eroc022

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Re: Holley carb Question
« Reply #4 on: April 14, 2007, 10:24:04 PM »
is it more like its flooding or more like its not getting gas ?
Eroc
Fixing the car that Restore A Muscle Car jacked up....

Offline turbota400

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Re: Holley carb Question
« Reply #5 on: April 14, 2007, 10:33:09 PM »
when I start it it seems like flooding since I have to hold it to the floor to start but the throttle has to be half way open for it to idle.  I checked the vac. secondary spring and it doesn't seem to be weak. 
Could it possibly be my vac. advance?  The Edelbrock coughs through the carb occasionally when I accelerate but runs normal otherwise.  I was hoping it was just the carb needing rebuilt so I tried the Holley and here we are.
Shawn
1972 Chevy C-10
1980 Trans Am Pace Car - 428 ci Poncho in the works
1992 S-10 2WD- Work Bomber/Gas saver
1997 Chevy X-cab 4x4 - Vortec 350

Offline eroc022

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Re: Holley carb Question
« Reply #6 on: April 14, 2007, 10:43:48 PM »
sounds like a timing issue there....if its coming back through the carb on one...and starting hard on the other then thats where id start
Eroc
Fixing the car that Restore A Muscle Car jacked up....

Offline turbota400

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Re: Holley carb Question
« Reply #7 on: April 14, 2007, 10:46:41 PM »
I'll try a new vac. advance in the morning and let you know.  Thanks.
Shawn
1972 Chevy C-10
1980 Trans Am Pace Car - 428 ci Poncho in the works
1992 S-10 2WD- Work Bomber/Gas saver
1997 Chevy X-cab 4x4 - Vortec 350

Offline turbota400

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Re: Holley carb Question
« Reply #8 on: April 15, 2007, 04:25:25 PM »
I replaced the vac. adv. this morning and pulled the vac. secondaries apart and the diaphram on the secondaries had a small tear in it.  Runs great now.  thanks for the help.
Shawn
1972 Chevy C-10
1980 Trans Am Pace Car - 428 ci Poncho in the works
1992 S-10 2WD- Work Bomber/Gas saver
1997 Chevy X-cab 4x4 - Vortec 350

Offline Joker (§ir£Ğragon)

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Re: Holley carb Question
« Reply #9 on: April 15, 2007, 04:31:21 PM »
Sweet!
Larry


Offline turbota400

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Re: Holley carb Question
« Reply #10 on: April 15, 2007, 05:16:54 PM »
Now if I could just get the T/A done....
Shawn
1972 Chevy C-10
1980 Trans Am Pace Car - 428 ci Poncho in the works
1992 S-10 2WD- Work Bomber/Gas saver
1997 Chevy X-cab 4x4 - Vortec 350