SBC 350-- run on - 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 03-26-2006, 12:53 PM
Theresa Shank's Avatar
Member
 
Join Date: Dec 2004
Location: Noblesville
Age: 71
Posts: 105
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
SBC 350-- run on

We have a SBC 350 in our street rod. It is pre-electronic ignition, so it is probably a mid 70's version. Problem is that when you shut engine off it wants to run on and jump around. We pulled plugs and they do not appear to have a lot of carbon build up, timing is set at about 12 degrees. Problem seems worse when engine is hot, if you shut it off in gear it will act normal? Any suggestions would be appreciated.... THANKS... THERESA

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-26-2006, 01:12 PM
1969NovaSS's Avatar
turbo lag......yeeeeehaaaaaaw
 
Last photo:
Join Date: Feb 2005
Location: oxnard,ca
Age: 27
Posts: 685
Wiki Edits: 0

Thanks: 0
Thanked 4 Times in 4 Posts
engine run on

I recently had this problem with my friends engine i boult for him with a demon carb. The transition slot was open to far and just closed it up some. Other then that i would say retard/advance the timing some to see if ti gets better or worse.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-26-2006, 03:33 PM
DHMag's Avatar
Registered User
 
Last photo:
Join Date: Jun 2005
Location: InCahoots, Texas
Posts: 302
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
advancing the timing will only worsen the dieseling, try retarding it a few degrees.

Dale
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 03-26-2006, 04:48 PM
57 Chevy's Avatar
Registered User
 
Join Date: Dec 2005
Location: Montana
Posts: 156
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Dbl post, sorry

Last edited by 57 Chevy; 03-26-2006 at 05:03 PM.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 03-26-2006, 04:49 PM
57 Chevy's Avatar
Registered User
 
Join Date: Dec 2005
Location: Montana
Posts: 156
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
In my limited knowledge, The throttle stop screw is open too far. Turn it down and readjust the idle speed with the idle screws.

If your dist still has points in it, take a look at Pertronix or some other electronic replacement. I did and saw a big difference in low end torque and idle.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 03-26-2006, 10:26 PM
Member
 
Last photo:
Join Date: May 2003
Location: Shreveport LA
Age: 64
Posts: 5,103
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Try the cheap stuff first. Lower your idle speed a bit & see if it doesn't stop.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 03-26-2006, 11:42 PM
docvette's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Rebuild an alternator Last photo:
Join Date: Mar 2004
Location: Lafayette, california
Age: 62
Posts: 7,362
Wiki Edits: 12

Thanks: 0
Thanked 6 Times in 3 Posts
Doc here,

Lower the Idle speed if you still have adjustment left..First.

You want about 750 Manual, and 950 Automatic for curb idle..Ballpark

After you achieve that, toss a timing light on it and check your Static timing with the Vacuum advance pulled and plugged..It will probably be retarded if it was set up at a high idle..Reset it to about 12 degrees.

Other sources of High Idle are major Vacuum leaks..so take a little time to inspect all your Vacuum Hoses for cracked , rotted or just plain fallen off conditions.Don't forget the power brake booster, Modulator Valve and PCV valve..

If those are good, spray the induction system down with Carb cleaner, anywhere it speeds up you have a leak..repair as needed.

Doc
__________________
Aftermarket Solutions
Electronic & Electrical
Innovations
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 03-27-2006, 03:52 AM
budthespud's Avatar
Diehard Chevy Guy
 

Last journal entry: Getting rid of the old and Adding the New
Last photo:
Join Date: Oct 2005
Location: Madoc, Ontario Canada
Age: 55
Posts: 200
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Checking for Vac Leaks

I found the best way to check for vac leaks is with propane. If you have a standard propane tank (hand held) take the end off the valve and put a 2 foot hose on the end. Start your vehicle and turn the propane on and run the hose all over the vac lines and the carb. If the RPM's pick-up then you have a leak. This is much better than spraying carb cleaner all over your engine. I agree with the timing issue but also too I had the same problem with a 350 motor and it ran best on high octane from Sunoco/Shell etc...Good luck!!
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 03-27-2006, 07:31 AM
Dave E Shank's Avatar
Member
 
Join Date: Apr 2002
Location: Fishers, Indiana
Age: 70
Posts: 676
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
It sounds like we need to work on idle setting and maybe use a octane booster. I will also check for vacuum leaks..... THANKS.... DAVE & THERESA
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 03-27-2006, 08:51 PM
pmeisel's Avatar
Glad the Jeep is on the road
 
Last wiki edit: How to identify a Ford V8
Join Date: Jan 2004
Location: Meridian MS & Vermilion Ohio
Age: 58
Posts: 814
Wiki Edits: 8

Thanks: 0
Thanked 1 Time in 1 Post
May not be your problem, but I had one on the Jeep that I attributed to carbon buildup... got it cleaned up good and the problem was still there.... checked all the vacuum lines and found that I had the distributor advance running to manifold vacuum rather than ported vacuum from the carb, which meant that some advance stayed in when the throttle went closed... changed the line and the problem went away.

Coincidence? maybe -- 24 beers in a case, 24 hours in a day....
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
Distributor Tuning and Theory - Part 1 Rick WI Engine 35 04-26-2011 12:38 AM
Why not a 350 sbc? bowtieorbust Engine 29 09-05-2008 09:43 AM
I'm building a sbc 350 need input PLEASE the ernster Engine 8 07-13-2005 01:56 PM
Late model 350 SBC Question Smoker113 Engine 3 02-19-2005 10:12 PM
350 sbc crate motor questions bentwings Engine 7 10-29-2002 08:03 PM


All times are GMT -6. The time now is 10:23 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.