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 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 09-14-2019, 08:15 PM   #1
fordguy40
Registered User
 
Join Date: Feb 2018
Location: Montclair, CA
Posts: 149
Question Possible Quadrajet issue....surging at WOT...vacuum leak?

Distributor, wires, plugs, and fuel pump are new. Timing set to 16* initial, distributor provides 20* mechanical, vac. advance disconnected to eliminate a variable. Goodwrench 350 with around 5k miles on it. Carb has less than 100 miles on complete rebuild by me. Starts, idles, and runs at part throttle perfectly. Just started driving it a little harder and it has started bucking and surging under load, such as merging onto the freeway and holding the throttle open to maintain acceleration. When I left off the gas, it returns to normal. No backfiring, no smoke, no stalling.

Noticed a few things about the carburetor that maybe you guys can help me with. Really beginning to think I've got a serious vacuum leak, even though the propane test showed nothing. First, the airhorn bolts were a bit loose and the idle came down a little as I torqued them. Going to pull the carb and tighten up everything that comes up through the bottom.

Second, even though the throttle shafts have been bushed, there was noticeable play in the primary shaft when I took it apart. Is there any play allowable here?

Also, can't get it to idle below 750 rpm, even with the curb idle screw backed out all the way. The lever that the screw rides against also does not touch the forward stop on the carburetor body. Need to check the throttle butterfly alignment, but assuming they're not jammed, should the throttle shaft lever touch the carb body with the curb idle screw backed out and should I be able to kill the engine with the screw backed out all the way?
__________________
A few Fords and a couple of Chevys
fordguy40 is offline   Reply With Quote
 

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 11:02 PM.


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