accelerator pump questions - 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> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 10-05-2008, 11:06 AM
powered by 1.21 gigawatts
 
Last photo:
Join Date: Jan 2008
Location: bucks county pa
Posts: 71
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
accelerator pump questions

hey just picked up a 850 holley at a swap meet cheap that has 50cc accelator pumps
i have never done to many mods to carbs and was wondering was the benefit was to the larger pumps?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 10-05-2008, 06:20 PM
Rustydawg's Avatar
Cruzin w/Elvis in Bigfoots UFO
 
Last photo:
Join Date: Nov 2004
Location: Edmonton AB, Great White North
Age: 48
Posts: 248
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
The large pumps help to cover a "hole" or "flat spot" that occurs when the throttle is opened.

In the case of the carb you have it was probably the previous owner's effort to get the engine running right with a carb that was way too big.

Normally if there is plenty of engine underneath the carb the 30cc pumps would probably be enough.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 10-06-2008, 07:27 PM
Registered User
 
Join Date: Nov 2003
Location: Altoona/Eau Claire Wisconsin
Age: 44
Posts: 5
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Hey Guys...like rustydawg said, a 50CC pump kit purcase can allot of times be a cover up for some other carb/ignition problems and on most carbs a 30CC pump is enough.......But in the case of a 850 Holley, they have the largest venturi and butterfly diameter in the whole family of 4150 style carbs....at the top of each venturi it measures 1.600 and the butterflys measure 1.750...that leaves hardly no taper in the venturis and the air speed down low is real bad......causing allot of "transfer" style issues.....and a large "hole" of instantly opened up CFM introduced to the engine, hence making it nessesary for the bigger 50CC pumps to help cover up the flat spot.....If your engine is realitivly healthy then you should keep the 50CC pumps on there becasue you will probably need them.......Later, Jesse @ BIGS!!
Reply With Quote Quick reply to this message

Recent Engine 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
Two questions about a BBC RObs71Nova Engine 10 07-03-2012 02:55 PM
Some B&M 250 questions, JimDavis maybe? kick_the_reverb Engine 6 05-15-2006 10:26 AM
Suspension-Brakes-Steering Common Questions Jon Suspension - Brakes - Steering 0 10-16-2003 03:19 PM
Questions, questions, questions? slider in wa Transmission - Rearend 2 09-27-2003 02:01 PM


All times are GMT -6. The time now is 11:04 PM.


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.