Editing How to rebuild a Rochester Quadrajet 4MV carburetor (section)
Jump to:
navigation
,
search
=====Accelerator pump assembly===== If the accelerator pump wasn't working correctly, be sure to attach the linkage to the pump arm hole nearest the pivot to get the biggest pump shot. You can try the smaller shot and if that works well, use it. There are several different accelerator pump rod lengths used depending on the carb, if it's the wrong length this can cause the pump to work poorly. If the springs are reversed and the return spring that should be under the pump assembly is used as the override spring on the shaft, and the override spring is used under the assembly, that can cause it to work poorly. Sometimes the fuel filter spring gets mixed up with the accelerator pump springs as well. If the piston seal is wrong it can have a hard time pushing fuel and/or allowing the pump to refill. There's a ball that acts as a check valve under a screw in the float bowl, driver side. Be sure the ball is in place and sealing as it should. The check ball seat can be re-formed by carefully tapping an old check ball against the seat using a small punch and light mallet/hammer. Sometimes the accelerator pump bore gets glazed where it doesn't seal against the piston very well. The bore can be lightly honed using 600 grit wet or dry. I use a wooden dowel w/a piece of cloth wrapped around the dowel and the emery paper wrapped around the cloth. Then make like a boy scout starting a fire or like you're lapping a valve. You don't want to remove the finish, just break the glaze ever so lightly and to smooth the bore.
|
Editing help
(opens in new window)
Personal tools
Log in / create account
Namespaces
Page
Discussion
Variants
Views
Read
Edit
View history
Actions
Search
Navigation
Main Page
Recent changes
Random page
Help
All articles
Start a new article
Hotrodders forum
Categories
Best articles
Body and exterior
Brakes
Cooling
Electrical
Engine
Fasteners
Frame
Garage and shop
General hotrodding
Identification and decoding
Interior
Rearend
Safety
Steering
Suspension
Tires
Tools
Transmission
Troubleshooting
Wheels
Toolbox
What links here
Related changes
Special pages
Terms of Use
Copyright
Privacy Policy
Your Privacy Choices
Manage Consent