The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 01-13-2021, 10:49 AM   #1
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Carb leak at choke location

I've got a manual choke Edelbrock carb that is leaking at one of the ports on that side. I don't have anything connected to the choke so it isn't being used.
I have little experience with carbs so I've only tightened both of the bolts on the side, don't want to go any tighter.

Would a rebuild kit address this issue or is there something else I need to look into?
Thanks.
Attached Images
 
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-13-2021, 11:43 AM   #2
Ol Blue K20
Proprietor of Dale's Corner
 
Ol Blue K20's Avatar
 
Join Date: Nov 2012
Location: Vacaville , CA
Posts: 15,829
Re: Carb leak at choke location

What kind of leak? Vacuum or gas.
__________________
"Some Days Chickens And Some Days Feathers"

Dale
XNGH ECV Sam Brannan 1004

R.I.P. 67ChevyRedneck
R.I.P. Grumpy Old Man
Ol Blue K20 is offline   Reply With Quote
Old 01-13-2021, 11:44 AM   #3
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

Gas
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-13-2021, 12:25 PM   #4
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Carb leak at choke location

You got gas there, it’s flooding.
Multiple things to check.
Could be trash in needle/seat, stuck float, sunk float or the most common flooding issue with edelbrocks carbs which is too much fuel pressure.
geezer#99 is offline   Reply With Quote
Old 01-13-2021, 01:00 PM   #5
Ol Blue K20
Proprietor of Dale's Corner
 
Ol Blue K20's Avatar
 
Join Date: Nov 2012
Location: Vacaville , CA
Posts: 15,829
Re: Carb leak at choke location

Quote:
Originally Posted by geezer#99 View Post
you got gas there, it’s flooding.
Multiple things to check.
Could be trash in needle/seat, stuck float, sunk float or the most common flooding issue with edelbrocks carbs which is too much fuel pressure.
x2
__________________
"Some Days Chickens And Some Days Feathers"

Dale
XNGH ECV Sam Brannan 1004

R.I.P. 67ChevyRedneck
R.I.P. Grumpy Old Man
Ol Blue K20 is offline   Reply With Quote
Old 01-13-2021, 02:14 PM   #6
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

Quote:
Originally Posted by geezer#99 View Post
You got gas there, it’s flooding.
Multiple things to check.
Could be trash in needle/seat, stuck float, sunk float or the most common flooding issue with edelbrocks carbs which is too much fuel pressure.
Ok. There's a good chance it could be trash, I think I could use getting the tank cleaned.
So for the carb, as I said, not much experience. Just best to start with a rebuild kit or start poking around at each possible issue?
As far as fuel pressure, I've got just a regular fuel pump.
Thanks.
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-13-2021, 02:30 PM   #7
Andy4639
Old member
 
Andy4639's Avatar
 
Join Date: Jan 2002
Location: Liberty, & Garden City S.C. , U.S.
Posts: 19,936
Thumbs up Re: Carb leak at choke location

As far as I know they don't make any kits that will fix the side bores on these. I had one a while back that the gas pedal linkage was sloppy. I called Edelbrock to see what to order. They said no kits available for these issue.

I found a local guy after buying a new carb. and he fixed it for me.
__________________
1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver
Seeing the USA in a 71


Upstate SC GM Truck Club
2013,14 and 2016 Hot Rod Pour Tour


http://upstategmtrucks.com/



Get out and drive the truck this summer and have some fun!
It sucks not being able to hear!

LWB trucks rule, if you don't think so measure your SWB!
After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.
Andy4639 is offline   Reply With Quote
Old 01-13-2021, 03:15 PM   #8
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Carb leak at choke location

Quote:
Originally Posted by Droff View Post
Ok. There's a good chance it could be trash, I think I could use getting the tank cleaned.
So for the carb, as I said, not much experience. Just best to start with a rebuild kit or start poking around at each possible issue?
As far as fuel pressure, I've got just a regular fuel pump.
Thanks.
Start it up and look in the carb.
You shouldn’t see any raw fuel while it’s idling.
If you do let us know.
Do you have any rubber hose on the fuel line from the pump to the carb?
geezer#99 is offline   Reply With Quote
Old 01-13-2021, 03:48 PM   #9
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

Quote:
Originally Posted by geezer#99 View Post
Start it up and look in the carb.
You shouldn’t see any raw fuel while it’s idling.
If you do let us know.
Do you have any rubber hose on the fuel line from the pump to the carb?
I'll give that a check.
On the rubber hose, yes I do. I've got a filter inline sitting along the frame and it's rubber from the filter to the pump. From the pump up it's about 50/50 hardline and rubber to the carb. I've got a second filter inline just prior to the carb.
The setup is how it was when I bought the truck, haven't done anything to change it.
Attached Images
 
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-13-2021, 05:04 PM   #10
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Carb leak at choke location

I’ve used a pair of pliers to gently squeeze rubber fuel line to reduce the flow. Acts like a fuel regulator. Less flow will likely stop any flooding you see inside. That will show fuel pressure is too high.
Sometimes when you release the hose the extra fuel can also help flush out any crap in the needle/seat.
geezer#99 is offline   Reply With Quote
Old 01-13-2021, 06:01 PM   #11
mr.mud1
Registered User
 
mr.mud1's Avatar
 
Join Date: Dec 2020
Location: Joggins Nova Scotia
Posts: 1,575
Re: Carb leak at choke location

hi,with regards to your carb problem.if it's leaking because it's flooding,as was already said you may have some crap in the needle and seat,not letting the flow of fuel stop or slow down when the float raises.i do a bunch of Quadrajets here and see one often that is flooding because the tank is full of crap.sometimes i am able to hit on the front of the carb by the fuel line with a rubber hammer,just easy and once in a while,the crap will dislodge and problem is solved,more often than not,i have to pull the top off and clean out the crap.sometimes you can get the air horn off without killing the gasket,sometimes,no such luck.if you have the carb apart,if it is stopped up with crap and it's dirt and rust and so on,the tank is dirty,but you might see bits of rubber,indicating a hose is failing.good luck.
mr.mud1 is offline   Reply With Quote
Old 01-13-2021, 06:19 PM   #12
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

I've got fuel sitting on both sides of the carb when running, see arrows.
Attached Images
 
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-13-2021, 06:32 PM   #13
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Carb leak at choke location

Try the hose trick.
Might be need for a regulator.
Or float adjustment.
geezer#99 is offline   Reply With Quote
Old 01-13-2021, 07:21 PM   #14
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

Tried the hose trick, squeezed it for around 30-40 seconds, no difference in idle or level of fuel in the carb. I pretty much had it clamped, not just restricted a bit.
Need to go longer?
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-13-2021, 07:41 PM   #15
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,494
Re: Carb leak at choke location

Don’t hurt to try longer.
geezer#99 is offline   Reply With Quote
Old 01-14-2021, 02:16 PM   #16
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

I'll give that another shot but I figure I'll just cut to the chase and pull the tank to get it cleaned and coated as well as get a rebuild kit for the carb. I'm pretty sure I have a lot of crud in the tank, the filters get clogged fairly easy.
No point in leaving the carb out of the equation.
Thanks.
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-15-2021, 09:43 AM   #17
tim_mc
Registered User
 
tim_mc's Avatar
 
Join Date: Jan 2019
Location: St Peters, MO
Posts: 430
Re: Carb leak at choke location

As you may have read on this site and elsewhere, Edelbrock carbs don't like more than 5-6psi of fuel. I installed a regulator and gauge, which really helped. The VDO gauge was made in the USA.

I rebuilt a 1405 before switching to an AVS2 1905. They are easy to rebuild in my opinion.
Attached Images
  
__________________
1967 C20, 350 SBC w/Comp roller cam, 700R4 w/3.42 posi, PS, 4-wheel PDB, Old Air AC & GM Tilt column.
tim_mc is offline   Reply With Quote
Old 01-24-2021, 11:38 AM   #18
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

Got the tank pulled and looks like it was needed. Rust is worse at the bottom. I've got a rebuild kit for the carb and need to get the tank dropped off for cleaning/coating.
As far as the carb goes, any recommendation on cleaning the exterior?
This is my first go round with doing a carb job, I think I can do the monkey see, monkey do thing on the rebuild part with Youtube help but not sure how to make the carb look better.
Any suggestions there?
Thanks.
Attached Images
  
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-24-2021, 03:49 PM   #19
mr.mud1
Registered User
 
mr.mud1's Avatar
 
Join Date: Dec 2020
Location: Joggins Nova Scotia
Posts: 1,575
Re: Carb leak at choke location

good deal,i figured your tank was full of crap.when i do carbs here,i dismantle them entirely,soak them in carb cleaner for a day or 2,rinse the pieces off with boiling water then blow it all out with compressed air and then it goes back together.if you're going to dismantle the carb completely,be careful,take your time and pay attention to the little parts and where they came from.you can buy carb cleaner at any parts store in a spray can.clean all the parts with the spray carb cleaner,you can use brake cleaner after that,there's a 100 ways to do it.if you were worried about getting it all apart,chances are,all your problem is in the float chamber.the dirt will collect there and on the needle and seats.you could cheat and just pull the top off and clean it out.nothing to it?
good luck.Greg
mr.mud1 is offline   Reply With Quote
Old 01-29-2021, 07:17 PM   #20
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

I've got it torn down and cleaned up, the procedure wasn't too bad, plenty of Youtube help just to make sure I didn't get anything in the wrong spot.

Is there a starting point for both of the idle mix screws on the front? I thought I had seen three half-turns out as a start but wasn't sure. Going by where they were before cleaning it up, I'm a good bit off of that.

Also, in the second pic, should I adjust the Idle Speed screw and High Speed Idle screw so the primary is sitting at a certain spot or any kind of a starting point also?

Thanks.
Attached Images
  
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-29-2021, 07:39 PM   #21
mr.mud1
Registered User
 
mr.mud1's Avatar
 
Join Date: Dec 2020
Location: Joggins Nova Scotia
Posts: 1,575
Re: Carb leak at choke location

i knew you could do it.i have no experience with these carbs but a carb is a carb sort of.when i do quadrajets,i always take the mixture screws out,one at a time,wire brush clean,gently and re-install them til they just bottom and turn them out a turn and a 1/2.they always start and then i adjust the carb with a vacuum gauge,i'm usually pretty close.i don't know about that low speed/high speed idle/are you sure that's what it has?i haven't done any of these carbs yet,maybe someone can chime in?i know most carbs,once the throttle is open passed the idle circuit,it's job is done?sorry i'm no more help.Greg
mr.mud1 is offline   Reply With Quote
Old 01-29-2021, 09:47 PM   #22
Steeveedee
Who Changed This?
 
Steeveedee's Avatar
 
Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,019
Re: Carb leak at choke location

Once you clean it up nice, check to see how much wiggle you get, especially in the primary throttle shaft. The Edelbrock carbs wear at the throttle shaft bore and need to be bushed at about 40k miles, in my experience.
__________________
~Steven

'70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper

Simi Valley, CA
Steeveedee is offline   Reply With Quote
Old 01-30-2021, 09:57 AM   #23
tim_mc
Registered User
 
tim_mc's Avatar
 
Join Date: Jan 2019
Location: St Peters, MO
Posts: 430
Re: Carb leak at choke location

Here's a link to the Edelbrock Performer & AVS carb owner's manual. I found it to be a good reference, especially for the float adjustment and calibration charts for dialing in the jets, metering rods & springs.

https://www.edelbrock.com/pub/media/...ers-manual.pdf
__________________
1967 C20, 350 SBC w/Comp roller cam, 700R4 w/3.42 posi, PS, 4-wheel PDB, Old Air AC & GM Tilt column.
tim_mc is offline   Reply With Quote
Old 01-31-2021, 09:42 AM   #24
Droff
Registered User
 
Join Date: Dec 2016
Location: OKC
Posts: 130
Re: Carb leak at choke location

I haven't noticed any excessive wiggle on the throttle shaft, it's pretty tight at this point.

Thanks for the link, I've found several sites for float adjustment and right now don't plan on fiddling with much else in the carb for performance.

I'm going to replace some of the fuel line but not all of it, what's the best way to get the old lines cleaned out before I start pumping fuel through them?

Thanks.
__________________
'68 GMC 3/4 Ton
350, 700R4
Droff is offline   Reply With Quote
Old 01-31-2021, 09:57 AM   #25
mr.mud1
Registered User
 
mr.mud1's Avatar
 
Join Date: Dec 2020
Location: Joggins Nova Scotia
Posts: 1,575
Re: Carb leak at choke location

hi,sounds like you're making progress.the fuel lines shouldn't be too dirty,fuel flowing through them should keep them fairly clean?can you see inside the lines you want to clean?if you're not removing them to clean them or verify they're clean.you could pump some fuel through them just turning over the motor on the key but probably not safe to have fuel around like that if you had a spill,some fumes and a spark,it wouldn't be good.depending on what lines you're not replacing,and how hard it would be to remove them,just take them off and shoot some brake cleaner through them.check the condition of any of the rubber hose,that you don't have it breaking up in little pieces that will mess up a clean carb.all the best.Greg
mr.mud1 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:24 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com