roshester quad jet carb. - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 08-30-2011, 09:11 PM
Registered User
 
Last photo:
Join Date: Aug 2011
Location: newzealand
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
roshester quad jet carb.

Gota roshester quad jet carb. It's not running so great,the truck wont run unless i up some fuel down the carb then hook the fuel line bak up.. pulled the filter out of it and it was squashed up inside the housing.pulled it out, it made not diffence. Just a case for a clean do you think?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-31-2011, 03:02 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by farmer_turbo_350
Gota roshester quad jet carb. It's not running so great,the truck wont run unless i up some fuel down the carb then hook the fuel line bak up.. pulled the filter out of it and it was squashed up inside the housing.pulled it out, it made not diffence. Just a case for a clean do you think?
Needs a rebuild. If the fuel drains out overnight and you have to crank it over for a long time, or prime it by pouring gas down the carb , the main wells are leaking- a common problem w/the earlier Q-jets.

Tell us about the induction system on the engine below. I see a Q-jet throttle plate, then what else is there?

Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-31-2011, 03:16 AM
Registered User
 
Last photo:
Join Date: Aug 2011
Location: newzealand
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
poor mans injection.

Ok that sounds like the problem i am having. i can crank the engine all i like and it wont start. but once i prime it with gas it will run. tho it doesn't want to, i have the rev's turned up to keep it alive.


the system below is a dedicated lpg intake."poor mans injection"
there is no petrol carb on it. it makes it run alot better then a duel fuel arangement and i dont have any problems of over fueling or straving the engine when on rough unlevel turrain.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-31-2011, 06:06 AM
willowbilly3's Avatar
Member
 

Last journal entry: Body mods
Last photo:
Join Date: Jun 2004
Location: Black Hills, South Dakota
Age: 61
Posts: 1,208
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have rebuild hundreds of Q jets and never saw the fabled main well plug leakage everyone blames them for. It seems to me like they found out it was actually the fuel going back down the line and came up with the fuel filter with the little check valve in it. Almost every Q jet problem I have seen was just a dirty carb and more commonly, problems with the choke controls. They also wear out the throttle shaft bushings but that mostly causes idle issues.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-31-2011, 11:04 AM
Registered User
 
Last wiki edit: Wheelbase database Last photo:
Join Date: Jan 2007
Location: Virginia
Posts: 3,519
Wiki Edits: 1

Thanks: 6
Thanked 146 Times in 133 Posts
First question is, do you have a Rochester Quadrajet spread bore or a 4GC square bore (called QuadJet by Rochester). Yeah, it's confusing, but these are two completely different carbs.

I agree about the leaking main well plugs. This ONLY applies to the early 1966-67 Qjets that used the pressed in sheet metal cap plugs. All Qjets built since 1968 use spun-in aluminum plugs that DO NOT leak.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-31-2011, 03:51 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Couple things here:

The man said he has a Q-jet. Instead of doubting him, I will believe he knows the difference between a 4G and a 4M.

Quote:
Originally Posted by cobalt
...the main wells are leaking- a common problem w/the earlier Q-jets
The leaking wells became a problem w/the intro of the Q-jet-- in 1965. Q-jets between 1965-'68 w/the cup plugs virtually ALL leaked, and anyone who's dealt w/these carbs knows this very well.

Carb kits from then to this day have included those (worthless) black triangular tampons made to stop the well leak. For a week or two, anyway.

The aluminum sweged plugs are much more reliable, BUT- as has been found time and time again- they have to be verified to be leak-free, because they DO leak occasionally. No carb rebuilder worth his salt would build a carb w/o checking them over. I have a ground-down tap in my carb tools used for nothing but threading the well holes for plugging.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 09-01-2011, 02:31 PM
Registered User
 
Last wiki edit: Wheelbase database Last photo:
Join Date: Jan 2007
Location: Virginia
Posts: 3,519
Wiki Edits: 1

Thanks: 6
Thanked 146 Times in 133 Posts
Quote:
Originally Posted by cobalt327
Couple things here:

The man said he has a Q-jet.
No, he didn't. Read his O.P. again. He specifically said a "Quad Jet". Some 4GCs have "Quad Jet" cast into the body (and some have "4 Jet"), hence my question. Remember what happens when one ASSumes...
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 09-01-2011, 02:54 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
My mistake, if it IS a mistake. The OP did say "pulled the filter out of it and it was squashed up inside the housing." The 4G on my Buick 215 had an inline glass filter OEM. I don't know of any 4G's that used a filter like a Q-jet that would be in a housing, and that could be "squashed up"- back then many filters were sintered and to be squashed up would take a hammer! That doesn't mean there aren't any- just that I've not seen one. Are there any like that? If not, I think I'll call it a Q-jet. If there are, then I guess he'll (the OP) will need to clear things up.

Take care.

Last edited by cobalt327; 09-01-2011 at 03:14 PM.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 09-02-2011, 10:33 AM
Registered User
 
Last wiki edit: Wheelbase database Last photo:
Join Date: Jan 2007
Location: Virginia
Posts: 3,519
Wiki Edits: 1

Thanks: 6
Thanked 146 Times in 133 Posts
No mistakes to worry about, I just wanted the OP to clarify what carb he actually had, which I what I asked originally.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 09-02-2011, 03:59 PM
Registered User
 
Last photo:
Join Date: Aug 2011
Location: newzealand
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
this carb is a quadrajet with small primarys and large secondarys
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 09-02-2011, 04:02 PM
Registered User
 
Last photo:
Join Date: Aug 2011
Location: newzealand
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
this one has electronic feed bak and a built in filter housing. it has a roughly 30mm long round paper type filter in it.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 09-02-2011, 04:33 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Are you using the PCM and the engine mounted sensors, etc. to control the carb or are you wanting to run the feedback carb without the computer? Or is the hard starting the main problem, or ?
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 09-02-2011, 08:48 PM
Registered User
 
Last photo:
Join Date: Aug 2011
Location: newzealand
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the starting problem is the main problem. i'm actually unsure of what is set up with the feed system; but i know what ever it is it was working. the main problem i have is the starting problem. It could be a vacuum leak so some discription, so that is the first place i will head i think.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 09-02-2011, 08:49 PM
Registered User
 
Last photo:
Join Date: Aug 2011
Location: newzealand
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
what is the pcm and engine mounted sences for?
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 09-02-2011, 09:37 PM
SSedan64's Avatar
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Macon, GA.
Age: 50
Posts: 6,016
Wiki Edits: 0

Thanks: 0
Thanked 46 Times in 46 Posts
Quote:
Originally Posted by farmer_turbo_350
what is the pcm and engine mounted sences for?
The CCC QuadraJet is computer controlled, it uses feedback from the Engine Sensors to the ECM/EngineControlModule to tune the Carb. If the ECM or Sensors are deleted it will not operate.

http://arrc.epnet.com/autoapp/9100/9...JUSTMENTS_.htm
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Carb Question Holley Quad Jet Brandonion1985 Engine 18 01-06-2011 09:52 AM
4412 carb or 750 4 barrel quad david73 Engine 0 06-22-2010 06:00 PM
quad cam gm v6 emc racing Engine 6 01-10-2009 09:33 PM
Dual Quad vs Single big carb 69ChevelleAddict Engine 10 05-29-2006 06:28 PM
305 quad carb 69GrandPrix Engine 1 12-07-2004 05:11 PM


All times are GMT -6. The time now is 07:00 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.