More information needed like what year? What engine? Has it been modified before or stock? What work has been done?
Help needed with a grumpy old lady!!!
Thread Starter
Intermediate
Joined: May 2009
Posts: 37
Likes: 0
From: Houston Texas
Help needed with a grumpy old lady!!!
although we have started her up 5-10 times and taken her to around 4500 rpm's, she continues to backfire, flame randomly out of the carburator, and overall very grumpy!!! we have tried some carb and choke cleaner although it has not done much, although we have some fuel additive stuff to "clean out the carburator" that will go in after the next 5 gallons of gas we give 'er. should we wait and see what it does? or should we try something more potent? like the starting spray stuff?? any tips?
Melting Slicks
Joined: Jun 2005
Posts: 2,239
Likes: 74
From: Palatine, Peoples Republic of Illinois
St. Jude Donor '09-'10-'11-12-'13-'14-'15-'16-'17-‘18
NCM Sinkhole Donor
I think to get a good reply you may have to post a few more details like what engine and carb; stock or modified; what has been done so far. Sounds like a timing issue though if you're getting flames from the carb. ??
Burning Brakes
Joined: Aug 2005
Posts: 1,164
Likes: 1
From: Europe, France
You said "old lady", hmmm. Generally, I don't use carb cleaner on a brand new carb, so maybe old carb too 
Check fuel level in the fuel bowls,
Check fuel pressure ( 4 - 7 PSI ),
Look for clogged fuel filters,
Remove air cleaner and check squirters,
Check timing,
Check spark plugs color ( wet, fouled, bone white )
If the car didn't run for a long time, you could have old fuel deposits ( kind of varnish ) inside the carb.
Carb cleaner in the venturies WILL NOT REMOVE them.
AND a picture and some specs could help to diagnose
Check fuel level in the fuel bowls,
Check fuel pressure ( 4 - 7 PSI ),
Look for clogged fuel filters,
Remove air cleaner and check squirters,
Check timing,
Check spark plugs color ( wet, fouled, bone white )
If the car didn't run for a long time, you could have old fuel deposits ( kind of varnish ) inside the carb.
Carb cleaner in the venturies WILL NOT REMOVE them.
AND a picture and some specs could help to diagnose
Last edited by 73StreetRace; Jul 3, 2009 at 04:36 AM.
Advanced
Joined: Nov 2008
Posts: 99
Likes: 0
although we have started her up 5-10 times and taken her to around 4500 rpm's, she continues to backfire, flame randomly out of the carburator, and overall very grumpy!!! we have tried some carb and choke cleaner although it has not done much, although we have some fuel additive stuff to "clean out the carburator" that will go in after the next 5 gallons of gas we give 'er. should we wait and see what it does? or should we try something more potent? like the starting spray stuff?? any tips?
Plug wires going to the wrong cylinder(s)? That is, if you put new wires on or monkeyed with them?
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Burning Brakes
Joined: Jun 2004
Posts: 872
Likes: 3
From: Cortlandt Manor New York
All the junk you are pouring down the carb will not slove the problem. Sometimes that stuff will help minimally but it will not solve a problem like yours.
You need to post more details. Engine, carb, new, rebuilt, sitting a while, first time running, what has been done to engine, stock or modified????
The more you tell the more help you can get. Previous suggestions are a good place to start - timing, or plug wire routing but tell us how you got to this point..
You need to post more details. Engine, carb, new, rebuilt, sitting a while, first time running, what has been done to engine, stock or modified????
The more you tell the more help you can get. Previous suggestions are a good place to start - timing, or plug wire routing but tell us how you got to this point..
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
although we have started her up 5-10 times and taken her to around 4500 rpm's, she continues to backfire, flame randomly out of the carburator, and overall very grumpy!!! we have tried some carb and choke cleaner although it has not done much, although we have some fuel additive stuff to "clean out the carburator" that will go in after the next 5 gallons of gas we give 'er. should we wait and see what it does? or should we try something more potent? like the starting spray stuff?? any tips?
Burning Brakes
Joined: Mar 1999
Posts: 1,047
Likes: 3
From: CA
Your profile says you have a 71. If it has points, put a new set in and adjust to specs. Then set the timing. From this point on it will be easier to diagnose. If you have points and they are worn or out of adjustment you will never get it to run properly.
Last edited by 71406; Jul 4, 2009 at 02:19 PM.
Cruising
Joined: Jun 2007
Posts: 11
Likes: 0
Background on the Corvette in question:
1971 coupe base engine, auto, air, engine rebuilt in 1985, about 3000 miles on the engine since rebuild. Everything stock, everything mechanical in great working condition the last time she was driven 18 years ago. Garage stored all these years. Last month replaced fuel tank, rubber fuel lines, fuel pump, external and internal fuel filters, changed oil + filter, coolant, new spark plugs. Old points, a little film of rust on them but cleaned up fine with a few strokes of emery board. Stock Qjet. Engine running roughly but will not idle in park or drive. Car still not drivable (no brakes, haven't checked out steering, suspension, or transmission yet, needs tires).
It's worth rechecking we got the right plug wires back on the right spark plugs after we changed the plugs. Have not adjusted timing so wouldn't expect it to be off just from sitting. I figure a good Qjet rebuild would help a lot but would rather not do that unless really necessary since I've only done it once some 20+ years ago.
Thanks for your help!
-pak
1971 coupe base engine, auto, air, engine rebuilt in 1985, about 3000 miles on the engine since rebuild. Everything stock, everything mechanical in great working condition the last time she was driven 18 years ago. Garage stored all these years. Last month replaced fuel tank, rubber fuel lines, fuel pump, external and internal fuel filters, changed oil + filter, coolant, new spark plugs. Old points, a little film of rust on them but cleaned up fine with a few strokes of emery board. Stock Qjet. Engine running roughly but will not idle in park or drive. Car still not drivable (no brakes, haven't checked out steering, suspension, or transmission yet, needs tires).
It's worth rechecking we got the right plug wires back on the right spark plugs after we changed the plugs. Have not adjusted timing so wouldn't expect it to be off just from sitting. I figure a good Qjet rebuild would help a lot but would rather not do that unless really necessary since I've only done it once some 20+ years ago.
Thanks for your help!
-pak