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Carburetor problems


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KarenWS
Novice

Jan 8, 2012, 3:47 PM

Post #1 of 17 (2755 views)
Carburetor problems Sign In

I have a 1975 Camaro with a 1997 V-8 Vortec engine out of a Suburban, and a 4 bbl Holley carburetor.
I've been having problems keeping the motor running, had the carburetor rebuilt with a kit from O'Reilly's. Also changed the plugs and wires.
I've had two different "backyard" mechanics mess with it, and we've got it where it will stay running in idle, but have had problems keeping the motor running when we put it in gear. I have no idea what to do next.
I am looking to sell the car, but want it in running condition so they can at least get it home. Short of putting a new carburetor on it, what can we try?
Thank you,
Karen


nickwarner
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Jan 8, 2012, 3:53 PM

Post #2 of 17 (2738 views)
Re: Carburetor problems Sign In

If the carb was put together right it shouldn't need replacement. It needs to be tuned and adjusted. You need someone very familiar with this sort of thing to do it right. Also, verify the ignition timing and advance are adjusted right and you have no vacuum leaks. Does the idle change when you press down the brake pedal? If that affects it you would have a leaking brake booster. It may be something very simple that is being overlooked that is causing the problem.


KarenWS
Novice

Jan 8, 2012, 3:58 PM

Post #3 of 17 (2735 views)
Re: Carburetor problems Sign In

Yes, the idle changes when you step on the brakes. It starts to choke up at that point, then putting it in gear makes the motor die. The brake fluid is low, will get that looked at this week. I sure hope it's something simple! Thank you for your response!


nickwarner
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Jan 8, 2012, 4:02 PM

Post #4 of 17 (2729 views)
Re: Carburetor problems Sign In

Brake fluid being low would indicate a leak in the brake hydraulic system. It would be a seperate issue to look at but won't affect the way the engine runs. The vacuum booster that the master cylinder mounts to uses engine vacuum to make it easier for you to use the brakes. If it leaks vacuum then your engine vacuum will drop when you hold the brakes and can stall or nearly stall your engine. Without trying to put it in gear, push and hold the brakes. If it starts sputtering out and trying to die then replace the vacuum booster. Its probably original and after all those decades under the hood no surprise to see it go out.


Hammer Time
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Jan 8, 2012, 4:05 PM

Post #5 of 17 (2726 views)
Re: Carburetor problems Sign In

Has this motor ever run good with that setup?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



KarenWS
Novice

Jan 8, 2012, 4:07 PM

Post #6 of 17 (2721 views)
Re: Carburetor problems Sign In

Thank you, Nick. I'll have him replace the vacuum booster and hope that does it. He did check the vacuum while it was in idle, but not with the brake pedal depressed.
Thank you so much for the info!
Karen


Hammer Time
Ultimate Carjunky / Moderator
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Jan 8, 2012, 4:10 PM

Post #7 of 17 (2716 views)
Re: Carburetor problems Sign In


Quote
I'll have him replace the vacuum booster and hope that does it


Don't do that until you have actually proven it has a problem. All you have to do is simply pinch off the hose to see if that corrects the problem.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



KarenWS
Novice

Jan 8, 2012, 4:10 PM

Post #8 of 17 (2713 views)
Re: Carburetor problems Sign In

Hammer - it's been running great until this past summer. Have had these problems since then. Spent almost $400 in repairs already, could have bought a new carb.


nickwarner
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Jan 8, 2012, 4:18 PM

Post #9 of 17 (2707 views)
Re: Carburetor problems Sign In

Hammer Time poses a question I should've asked. Did this ever run right as it is set up? If you want to try an easy test, pinch off the rubber hose running from the intake manifold to the brake booster. Then hold the brake so the car doesn't run off and put it in gear. See if you can do that without stalling. Then you are assured its the booster causing the issue.


KarenWS
Novice

Jan 8, 2012, 4:20 PM

Post #10 of 17 (2707 views)
Re: Carburetor problems Sign In


In Reply To

Quote
I'll have him replace the vacuum booster and hope that does it


Don't do that until you have actually proven it has a problem. All you have to do is simply pinch off the hose to see if that corrects the problem.


Thanks Hammer. We'll check it out first. He says it might just be the vacuum hose. Said it was cracked.


KarenWS
Novice

Jan 8, 2012, 4:26 PM

Post #11 of 17 (2702 views)
Re: Carburetor problems Sign In


In Reply To
Hammer Time poses a question I should've asked. Did this ever run right as it is set up? If you want to try an easy test, pinch off the rubber hose running from the intake manifold to the brake booster. Then hold the brake so the car doesn't run off and put it in gear. See if you can do that without stalling. Then you are assured its the booster causing the issue.


I'll print out these post responses and let him try these suggestions first. He said the brakes are bad and it's probably the booster causing that problem, too.
Thank you both for your help!


nickwarner
Veteran / Moderator
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Jan 8, 2012, 4:29 PM

Post #12 of 17 (2701 views)
Re: Carburetor problems Sign In

The hose being cracked would leak vacuum all the time. Definately replace it and closely look at all the other vacuum hoses. The hose is cheap, so if there is any question about it replace it. Multiple small leaks add up to a big problem together. No matter what new parts you replace, if the hoses leak vacuum this will never run right.


KarenWS
Novice

Jan 8, 2012, 4:34 PM

Post #13 of 17 (2697 views)
Re: Carburetor problems Sign In

I definitely will! Heck, if I get it running really good again and get the brakes fixed, I may end up keeping it!


dr.donut
User

Jan 9, 2012, 6:37 AM

Post #14 of 17 (2665 views)
Re: Carburetor problems Sign In

if you rebuilt that holly carb on your own I wouldn't assume it's O.K. those things are like a swiss watch


Tom Greenleaf
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Jan 10, 2012, 9:32 AM

Post #15 of 17 (2638 views)
Re: Carburetor problems Sign In

Notes: It didn't change "rebuilding" the carb so may not be the issue. Brake booster as that changes it is on the list as mentioned already. Worn or leaking brake parts just sitting there shouldn't alter engine performance except for vacuum to (hose) or booster and if you find that bad get a new check valve right at the booster too - in fact they are pretty cheap so try that first but unless cracked probably not it but it could break at the age just taking it out,

T



re-tired
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Jan 10, 2012, 11:33 AM

Post #16 of 17 (2632 views)
Re: Carburetor problems Sign In


In Reply To
Yes, the idle changes when you step on the brakes. It starts to choke up at that point, then putting it in gear makes the motor die. The brake fluid is low, will get that looked at this week. I sure hope it's something simple! Thank you for your response!



I have seen master cylinders leak from the piston into the booster. The fluid damages the diaphram . Unbolt the master cylinder and check for seepage .


LIFE'S SHORT GO FISH


KarenWS
Novice

Jan 10, 2012, 4:51 PM

Post #17 of 17 (2627 views)
Re: Carburetor problems Sign In

Thank you, Dr. Donut, Tom and Re-Tired! I have noted all these things to have checked out this weekend. I really appreciate everyone's input!
Karen






 
 
 






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