C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Carb Question

Thread Tools
 
Search this Thread
 
Old Aug 24, 2013 | 10:28 AM
  #1  
dbarnesid's Avatar
dbarnesid
Thread Starter
Cruising
 
Joined: May 2013
Posts: 14
Likes: 0
From: Boise Idaho
Default Carb Question

I have a '72 with an original Q Jet. The Q Jet has been rebuilt two months ago by a very good vette mechanic. Engine rebuilt 5,000 miles back and tyranny rebuilt two days ago. Car has been running well.

Last night I was driving home and it smelled a little rich when I started it but thought nothing of it. Four blocks later it died. Couldn't get it started and running well enough to get it home. It was extremely rich. Flooded. Black smoke and lots of it. When I gunned it black on left side and white on right sometimes. Mechanic stopped to help and was only mildly concerned about white smoke.

Car was towed home. This morning I got up, rapped the carb with butt end of a hammer a few times to loosen any wayward crap. Car starts, a little black smoke at first, then runs well but slightly rough. It's drivable for sure. Any thoughts or advice? I'm a little afraid to drive very far.
Reply
Old Aug 24, 2013 | 10:42 AM
  #2  
zuendler's Avatar
zuendler
Pro
10 Year Member
Conversation Starter
All Eyes On Me
Top Answer: 1
 
Joined: May 2011
Posts: 722
Likes: 58
From: Karlsruhe (Germany)
Default

needle and seat stuck. Known problem.
Reply
Old Aug 24, 2013 | 10:51 AM
  #3  
dbarnesid's Avatar
dbarnesid
Thread Starter
Cruising
 
Joined: May 2013
Posts: 14
Likes: 0
From: Boise Idaho
Default

Originally Posted by zuendler
needle and seat stuck. Known problem.
So no real fix other than rapping on carb as I did?

Thanks for your response. I've been a classic vette owner for four months so this is very new to me. (Though I was a gas station mechanic in 1972 while in college.)
Reply
Old Aug 24, 2013 | 11:49 AM
  #4  
Scott Marzahl's Avatar
Scott Marzahl
Le Mans Master
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2005
Posts: 6,339
Likes: 416
From: Seattle Area WA
Default

Probably some debris stuck in needle and seat. May have to open it up and clean it. Did the rebuilder replace the in-line filter, some people don't. Old cars, old gas tank can have some rust debris in system. Use stock filter.

Last edited by Scott Marzahl; Aug 24, 2013 at 11:51 AM.
Reply
Old Aug 24, 2013 | 02:39 PM
  #5  
jotto's Avatar
jotto
Melting Slicks
15 Year Member
 
Joined: Oct 2005
Posts: 2,056
Likes: 8
From: Redruth Cornwall
Default

Was the float replaced and height set correctly?

Black smoke is usually a sign of rich running but white smoke is not a good sign. Usually white is a head gasket or worse......

Hope you get it sorted soon.
Reply
Old Aug 24, 2013 | 02:40 PM
  #6  
dbarnesid's Avatar
dbarnesid
Thread Starter
Cruising
 
Joined: May 2013
Posts: 14
Likes: 0
From: Boise Idaho
Default

Originally Posted by Scott Marzahl
Probably some debris stuck in needle and seat. May have to open it up and clean it. Did the rebuilder replace the in-line filter, some people don't. Old cars, old gas tank can have some rust debris in system. Use stock filter.
Yes in-line filter replaced. Just ran it around town for an hour. Quite rough at first but would idle. At the end it seemed normal. Topped it off with 10% ethanol yesterday. Topped off again with real gas today.

Maybe crap in bad fuel? Very odd.

No black or white smoke now.

Last edited by dbarnesid; Aug 24, 2013 at 02:42 PM. Reason: More info.
Reply
Old Aug 24, 2013 | 07:30 PM
  #7  
oldalaskaman's Avatar
oldalaskaman
Le Mans Master
10 Year Member
 
Joined: Aug 2010
Posts: 9,272
Likes: 17
Default

you said 'vette' mechanic, I'd look for a 'carb' mechanic, member 'lars' would be my choice
Reply
Old Aug 24, 2013 | 07:39 PM
  #8  
7t9l82's Avatar
7t9l82
Le Mans Master
15 Year Member
Conversation Starter
Photogenic
Community Favorite
 
Joined: Oct 2010
Posts: 6,922
Likes: 839
From: melbourne florida
2023 C3 of the Year Finalist - Modified
Default

if i still had one thats where id go.
Reply

Get notified of new replies

To Carb Question

Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-1

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-2

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-3

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-4

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-5

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-6

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-7

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-8

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
story-9

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski




All times are GMT -4. The time now is 11:54 AM.

story-0
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-1
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-2
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-3
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-4
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-5
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-6
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-7
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-8
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE
story-9
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE