Did I do the right thing?
Thread Starter
Pro
Joined: Jun 2000
Posts: 668
Likes: 1
From: KY
Did I do the right thing?
My 76 has always been a cold natured beast. Really hard to start in cold weather and runs really rich until warm (rich like smell of raw fuel from the exhaust). I checked the choke and the choke plate was closed all the way tight with no gap. On the side of the Rochester carb, there's a little disk with rich and lean markings cinched down by 3 screws. I set the choke (pushed the gas to the floor once) and turned the disk toward lean a couple indicator marks. The choke plate is now craked open a little bit (about 1/8" or a little less).
It seemed to start much better and didn't smell like it was running rich.
Did I do the right thing, or will I be sorry?
Thanks,
Jeff S.
It seemed to start much better and didn't smell like it was running rich.
Did I do the right thing, or will I be sorry?
Thanks,
Jeff S.
Instructor
Joined: Jul 2001
Posts: 168
Likes: 4
From: central Washington state
Re: Did I do the right thing? (jeffnles1)
Jeff;
Sounds like you're moving in the right direction. There is a recommended pull-off dimension for your carburetor. By pull-off dimension, I mean the gap between the choke plate and the air horn, the "1/8 - in. gap" you described in your post. Assuming it's the stock Q-Jet. When the car is cold, before the engine starts, the choke should be completely closed. As soon as the engine fires, however, the choke should be pulled open a bit. There should be vacuum applied to the choke pull off to accomplish that. Not sure where the best place is to get the pull-off spec. While you're at it, check to see that the choke plate isn't binding or gummed up from varnish deposits. Check also to see that all the associated linkages are free and clean. Might be a good idea, when you have the time, to take the air cleaner off, start the car when it's overnight cold, and observe the action of your choke as the engine warms to operating temperature. If it's not operning up completely within a couple if minutes, you should be able to see why.
Sounds like you're moving in the right direction. There is a recommended pull-off dimension for your carburetor. By pull-off dimension, I mean the gap between the choke plate and the air horn, the "1/8 - in. gap" you described in your post. Assuming it's the stock Q-Jet. When the car is cold, before the engine starts, the choke should be completely closed. As soon as the engine fires, however, the choke should be pulled open a bit. There should be vacuum applied to the choke pull off to accomplish that. Not sure where the best place is to get the pull-off spec. While you're at it, check to see that the choke plate isn't binding or gummed up from varnish deposits. Check also to see that all the associated linkages are free and clean. Might be a good idea, when you have the time, to take the air cleaner off, start the car when it's overnight cold, and observe the action of your choke as the engine warms to operating temperature. If it's not operning up completely within a couple if minutes, you should be able to see why.
Race Director
Joined: Mar 1999
Posts: 10,258
Likes: 1
From: Calif.
Re: Did I do the right thing? (jeffnles1)
Don't think there are any hard-and-fast rules. Guidelines, sure, but RULES? Nah. Set up your car the way it works best for you and the way you drive it. They're all different and they all like different things. Sounds like you're on the right track.
Le Mans Master
Joined: Aug 2001
Posts: 8,164
Likes: 0
From: ohio
Re: Did I do the right thing? (jeffnles1)
yeah, you done fine i think. but as a point for the future, always be carefull when leaning out a carb. a rich condition is much much better than a lean condition. just something to keep in mind....
Thread Starter
Pro
Joined: Jun 2000
Posts: 668
Likes: 1
From: KY
Re: Did I do the right thing? (jeffnles1)
OK Guys, it seems to be much better. Went to my club meeting tonight. It sat since yesterday. Not too cold today, but chilly. It started right up, went on fast idle for a little while, choke opened up and she kicked down from high idle just fine.
Only thing is how can I tell if it's too lean. Any tell tale signs?
Thanks for the advice and help.
Jeff
Only thing is how can I tell if it's too lean. Any tell tale signs?
Thanks for the advice and help.
Jeff
Safety Car
Joined: Aug 2000
Posts: 3,909
Likes: 26
From: Clymer PA
Re: Did I do the right thing? (jeffnles1)
The only sure way to tell is to start pulling spark plugs. If your plugs have a black coating then you are running too rich. If your plugs have a whitish-grey glaze you are running lean.
As long as you didn't over-lean your mixture you should be fine.
As long as you didn't over-lean your mixture you should be fine.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Pro
Joined: Jun 2000
Posts: 668
Likes: 1
From: KY
Re: Did I do the right thing? (bence13_33)
Thanks, I'll keep an eye on it. I don't think I leaned it out too much. It did seem to run better tonight.
Now all I need to do is see if the vacuum secondaries are opening up properly.
Jeff
Now all I need to do is see if the vacuum secondaries are opening up properly.
Jeff
Instructor
Joined: Aug 2001
Posts: 215
Likes: 0
From: Concord Cal
Re: Did I do the right thing? (jeffnles1)
Why would backing off the choke cause a lean condition anywhere except when the engine is cold. I would rather have to restart the engine than change the convertor because it got fuel fouled from a choke set too tight. There is a screw on top that controlles the blade opening on the pull off.
Thread Starter
Pro
Joined: Jun 2000
Posts: 668
Likes: 1
From: KY
Re: Did I do the right thing? (oger)
Not a carb guy here. I do know the choke was closing too tight and causing it to run real rich at start up to the point it was hard to start and smelled like raw fuel coming from the pipes. Yuch :rolleyes:
Also, the choke plate didn't seem to be opening all the way. I moved the screw on the side of the carb that controls the choke and all seems well in the universe now. I'll just keep an eye on it for awhile.
Again, not a carb guy so I'm not too sure what, if anything, I have done.
Thoughts?
Jeff
Also, the choke plate didn't seem to be opening all the way. I moved the screw on the side of the carb that controls the choke and all seems well in the universe now. I'll just keep an eye on it for awhile.
Again, not a carb guy so I'm not too sure what, if anything, I have done.
Thoughts?
Jeff