68 Goat motor acceleration issue - Pontiac GTO Forum
User Tag List

LinkBack Thread Tools Display Modes
post #1 of 2 (permalink) Old 01-26-2013, 04:24 PM Thread Starter
Join Date: Jan 2013
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
68 Goat motor acceleration issue

I recently purchased a 68 GTO with a 400, 3 speed maual tranny. This car is an original survivor car with 67,000 miles. The previous owner stated that the Carter Quadra-Jet had been rebuilt recently, and it looks like it has been. The problem lies with wide open throttle the engine does not accelerate smoothly, it feels like it flutters/stumbles thru out the rpm range. The carb installed is a Carter Model 4887 S (F2). I was trying to find out if this is the correct application for the 68/400 motor. I do not think it is running rich, as there is no smoke when putting the hammer down. I am going to try and pull the sparkplugs tomorrow to see if there is any indications of running lean, How can you tell if the secondarys are opening all the way at full throttle applications? Could this be a timing issue? Is there a timing that works best other than what the specs state (retard vs advanced)?

Any suggestions would be greatly appreciated!!
68GOATinpa is offline  
Sponsored Links
post #2 of 2 (permalink) Old 01-26-2013, 06:57 PM
Join Date: Oct 2012
Location: Texas
Posts: 554
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
acceleration issues

Pull the air cleaner and look down the throat of the carb (with the engine off), and work the accelerator fully 2 or 3 times. You should see a good stream of gas shooting out of the discharge nozzles at the front. If not, it could be a bad accelerator pump, or a blocked passageway in the carb. Also, there should be a three hole positioning lever at the top of the accelerator pump, sometimes you can adjust the stumble out of it with that. It might be starving for gas. Check carefully for cracked vacuum lines. And with engine running, spray carb. cleaner around the base of carb, and all vacuum fittings- you will hear a change in rpm if there's a leak. Could be improperly adjusted floats, or a number of other things. Before you pull carb. though, thoroughly check your DISTRIBUTOR and ALL electrical components. (Points, HEI, etc...). If you have power brakes, make sure the booster isn't leaking. Post pics. if you can. Good luck.
gjones is offline  
Sponsored Links

  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO Complete Engine Compartment Discussion

Quick Reply

Register Now

In order to be able to post messages on the Pontiac GTO Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Similar Threads
Thread Thread Starter Forum Replies Last Post
Definition Of Acceleration y2kjammer 1964-1974 Tempest, Lemans & GTO General Discussion 3 05-17-2010 03:52 PM
Goat Quadrajet Issue HELP! jketelsen 1964-1974 Tempest, Lemans & GTO General Discussion 6 08-25-2009 03:47 PM
motor pinging on 69 goat clarkaim 1964-1974 Tempest, Lemans & GTO Complete Engine Compartment Discussion 7 06-17-2009 05:23 PM
71 goat with a 2004 motor & trans lazlo Engine Discussions 9 11-25-2007 08:48 AM
Motor Trend Dec '05 Issue Loubo In the News 6 11-07-2005 10:29 AM

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

For the best viewing experience please update your browser to Google Chrome