Whats the Problem??
Le Mans Master
Joined: Jun 2013
Posts: 7,002
Likes: 942
From: Colorado
2025 Corvette of the Year Finalist - Unmodified
2024 C8 of the Year Winner - Unmodified
2024 Corvette of the Year Finalist - Unmodified
2023 C7 of the Year Winner - Unmodified
2022 C7 of the Year Finalist - Modified
2020 C7 of the Year Finalist -- Modified
Had the same problem when I bought my 78. Put 91 octane in it, and it would die. Corvette shop scolded me for using 91. These engines were made to run on 85 octane. I've been putting 85 in it ever since, and she runs great. 
Drifting
Joined: Feb 2005
Posts: 1,879
Likes: 38
From: Los Gatos CA
I agree with leadfoot; the Q-Jet appears to be original, perhaps never off the car. That's a big plus. No offense, but please consider getting your car road worthy before driving. Start with your carb and a good tune. You will be much happier if she starts, idles and runs properly. And you gotta do it anyway, so why not do it now? Just my 2 cents...
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,033
Likes: 9,155
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
That carb wants to be rebuilt. With the varnish look on the outside, the inside is probably as bad. If you can build a model, you can rebuild a carb. And buy a carb cleaning dunk can. https://www.amazon.com/Gunk-CC3K-Car.../dp/B000ABGA4E.
http://quadrajetparts.com/quadrajet-...-c-128_33.html
Your local parts store should have it and they might have the carb rebuild kit. Now a days you might have to order the kit. If you leak gas all over the place and have a fire, you might loose more than your car.
With the accelerator pump leaking like that, most likely it has other problems with the floats and gaskets. Better to fix now and drive later than drive now and burn later. One backfire and its done
http://quadrajetparts.com/quadrajet-...-c-128_33.html
Your local parts store should have it and they might have the carb rebuild kit. Now a days you might have to order the kit. If you leak gas all over the place and have a fire, you might loose more than your car.
With the accelerator pump leaking like that, most likely it has other problems with the floats and gaskets. Better to fix now and drive later than drive now and burn later. One backfire and its done
Last edited by Rescue Rogers; Oct 1, 2016 at 10:12 AM.
Burning Brakes
Joined: Aug 2013
Posts: 1,231
Likes: 115
From: Yelm Wa
That's good, BUT you didn't answer the question. WHERE is the fuel "leaking" from? My guess, since it's an older car, is that the float in the fuel bowl is either damaged, causing fuel to get inside of it, so it doesn't "float" and shut off the fuel flow, causing fuel to "spill over", choking out the engine. Or, the float might simply be sticking, due to the inside of the fuel bowl being gummed up, again, causing the float to not work properly.
Again, however, WHERE are you seeing the "leakage"?
Again, however, WHERE are you seeing the "leakage"?
The carb gets blamed for a lot of drivability issues (not all warranted), but in this case, it would appear to be the culprit. That carb needs attention.
Instructor
Joined: May 2015
Posts: 118
Likes: 28
From: California
2016 C4 of Year Finalist
My '67 Mustang's Holley 4160 secondary bowl float sticks down almost every every time we start it up, it'll start flooding the engine and kills it within a few seconds if you don't keep the rpms up, you can see the fuel dumping out of the air bleeds and some gaskets, sounds like what yours is doing. I just tap the bowl with a hammer and it promptly un sticks, and runs fine. So I agree with the fellas, you need to rebuild your q jet, looks like it hasn't been touched in decades.
Last edited by Tubbafatt; Oct 1, 2016 at 11:16 AM.
Safety Car
Joined: Apr 2007
Posts: 3,849
Likes: 367
From: PHOENIX AZ. WHAT A MAN WON"T SPEND TO GIVE HIS ASS A RIDE
Thread Starter
Racer
Joined: Feb 2015
Posts: 336
Likes: 42
From: Grand Ledge, MI
Originally Posted by kenba
What part of rebuild the carb. are you having trouble understanding. Rebuild the carb.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!
Michael S. Palmer
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!
Joe Kucinski
7 Bolt-On Upgrades From Extreme Online Store to Level Up Your C6 Corvette
Pouria Savadkouei
Thread Starter
Racer
Joined: Feb 2015
Posts: 336
Likes: 42
From: Grand Ledge, MI
Fixed the problem, the gasket under the carb was broke and thats where the gas was coming from. I replaced that and clean the carb for now and plan on having it rebuilt by a friend in a week or so.
Is my vette stock?? HAHA
Joined: Oct 2015
Posts: 20,033
Likes: 9,155
From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Don't wait to long, we want to keep you around
Thread Starter
Racer
Joined: Feb 2015
Posts: 336
Likes: 42
From: Grand Ledge, MI
Originally Posted by Rescue Rogers
Don't wait to long, we want to keep you around
Burning Brakes
Joined: Oct 2015
Posts: 781
Likes: 113
PS make a note on the original carburator number on yours..Important to get the correct rebuild kit..or replacement carb..Even a like new replacement is gonna need to be properly tuned..timing maybe adjusted, fuel lines vac lines renewed-checked..NOT a job for a novice with a wrench..
Team Owner
Joined: May 2001
Posts: 87,294
Likes: 1,579
From: Western NY
If you have liquid fuel coming from there, when the engine is off, you have some sort of internal leak in the carb itself.
Thread Starter
Racer
Joined: Feb 2015
Posts: 336
Likes: 42
From: Grand Ledge, MI
Originally Posted by leadfoot4
Just for the record, "the gasket under the carb" is NOT a seal for fuel flow. That gasket seals the carb to the manifold, keeping outside air from entering the engine in an unmetered fashion. Any fuel that's in that area of the engine is in an atomized state, when the engine is running, as well as under vacuum, therefore it WON'T be leaking out on to the manifold.
If you have liquid fuel coming from there, when the engine is off, you have some sort of internal leak in the carb itself.
If you have liquid fuel coming from there, when the engine is off, you have some sort of internal leak in the carb itself.
Thread Starter
Racer
Joined: Feb 2015
Posts: 336
Likes: 42
From: Grand Ledge, MI
Originally Posted by jim in oregon
cdavis..I agree..DO not start or run your '78 UNTIL you get that old Rochester QJet PROPERLY rebuilt.. GO with a upgraded brass float while you are at it..DO not just hose it down with carb cleaner..That carb needs som experienced attention.. Not easy to find anyone locally who truly understands how to properly overhaul-rebuild-adjust-tune the old Q Jet Rochester..but they ARE out there..YOU'VE put a bit of time and effort into that '78 thus far..Don't burn it up..or shortcut what is needing done..Your friend in Oregon, Jim
PS make a note on the original carburator number on yours..Important to get the correct rebuild kit..or replacement carb..Even a like new replacement is gonna need to be properly tuned..timing maybe adjusted, fuel lines vac lines renewed-checked..NOT a job for a novice with a wrench..
PS make a note on the original carburator number on yours..Important to get the correct rebuild kit..or replacement carb..Even a like new replacement is gonna need to be properly tuned..timing maybe adjusted, fuel lines vac lines renewed-checked..NOT a job for a novice with a wrench..
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,328
From: At my Bar drinking and wrenching in Lafayette Colorado
- The carb needs a rebuild. It has a bad float which is causing the fuel seepage problems - the fuel leak has nothing to do with your base gasket.
- Do not trade it in/exchange it for a "rebuilt" carb.
- Have someone competent go through the carb and set it up for you.
- I can count on one hand the number of competent carb builders.
- Your uncle and friends are probably not on the list...
Lars
Last edited by lars; Oct 2, 2016 at 06:56 PM.
Drifting
Joined: Jul 2011
Posts: 1,697
Likes: 139
From: Syracuse NY
That's a beautiful, original carb, unmolested carb in rebuildable condition. My advise is as follows:
- The carb needs a rebuild. It has a bad float which is causing the fuel seepage problems - the fuel leak has nothing to do with your base gasket.
- Do not trade it in/exchange it for a "rebuilt" carb.
- Have someone competent go through the carb and set it up for you.
- I can count on one hand the number of competent carb builders.
- Your uncle and friends are probably not on the list...
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,328
From: At my Bar drinking and wrenching in Lafayette Colorado