Slant *        6        Forum
Home Home Home
The Place to Go for Slant Six Info!
Click here to help support the Slant Six Forum!
It is currently Mon Aug 15, 2022 2:57 am

All times are UTC-07:00




Post new topic  Reply to topic  [ 7 posts ] 
Author Message
 Post subject: Power drop off of idle.
PostPosted: Wed Apr 08, 2020 11:48 pm 
Offline
1 BBL (New)

Joined: Tue Nov 12, 2019 9:53 pm
Posts: 4
Car Model: 71 Dodge Demon
1st post, thanks in advance.
Fresh rebuild, everything is great except one issue. Takes off smoothly with tiny bit of pedal, give it a little more and it stumbles. Give it more gas and it takes off. Timing is 2.5 before .


Top
   
PostPosted: Thu Apr 09, 2020 10:34 am 
Offline
Turbo Slant 6
User avatar

Joined: Mon Jan 25, 2010 11:29 pm
Posts: 644
Location: Seattle, WA
Car Model: 75 Dart SE (2),75 Swinger, 74 Dart Sport,91 Ram RV
Idle fuel adjustment.

_________________
"Louise", a 1976 Dart Custom project, (now sadly reverted to being just an "organ donor" to our other project Darts.)


Top
   
PostPosted: Thu Apr 09, 2020 10:52 am 
Offline
Board Sponsor & Contributor

Joined: Thu Oct 31, 2002 5:39 pm
Posts: 23772
Location: North America
Car Model:
Welcome here. This is probably not caused by an improper idle mixture adjustment, no. It's more likely a problem with your accelerator pump and/or your vacuum advance. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. Also follow Tune-up parts and technique suggestions in this post, and make sure you've done a proper valve adjustment.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Image


Top
   
PostPosted: Thu Apr 09, 2020 4:42 pm 
Offline
1 BBL (New)

Joined: Tue Nov 12, 2019 9:53 pm
Posts: 4
Car Model: 71 Dodge Demon
Thanks for the replys. Valves are set per spec hot, Carb has not been rebuilt so I will try that as well. Question about vacuum adv. I set timing with vac adv plugged at dist and carb, when I reconnect idle goes up and timing marks seem to retard a lot. Does this mean my vac adv is working properly. asap I am going to upload a video of of the issue.
As far as drivability, there seems to be 2 modes of drivability with this. One is a light pedal that has smooth power at low RPM and doesn't seem to get into the powerband, just nicely shifts up with just a little more than idle. This would be perfect for economy driving. The second is when you give it enough gas to get into the powerband and it accelerates rapidly. The stumble happens between the two so I am leaning towards carburetor. Maybe it s the transition from the idle circuit that is the issue. Time to study the links you posted Dan. Thx 8)


Top
   
PostPosted: Thu Apr 09, 2020 4:47 pm 
Offline
Turbo Slant 6
User avatar

Joined: Sat Sep 13, 2014 8:25 am
Posts: 733
Location: Springtucky OR
Car Model:
Demonator wrote:
Thanks for the replys. Valves are set per spec hot, Carb has not been rebuilt so I will try that as well. Question about vacuum adv. I set timing with vac adv plugged at dist and carb, when I reconnect idle goes up and timing marks seem to retard a lot. Does this mean my vac adv is working properly.

It sounds to me like the vacuum advance hose is getting plugged into the wrong port on the carburetor.

_________________
--> Check out my FI Turbo build <--
--> And the race truck build project <--
--> The Diesel Corvette <--
Image


Top
   
PostPosted: Thu Apr 09, 2020 4:52 pm 
Offline
Board Sponsor & Contributor

Joined: Thu Oct 31, 2002 5:39 pm
Posts: 23772
Location: North America
Car Model:
Demonator wrote:
Carb has not been rebuilt so I will try that as well.


Definitely.

Quote:
I set timing with vac adv plugged at dist and carb, when I reconnect idle goes up and timing marks seem to retard a lot


No, the marks are advancing a lot. This means your distributor is receiving vacuum at idle, which it probably should not be—what year and model is your car, is it a Federal or California emission car (as applicable), what transmission does it have, and which carburetor?

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Image


Top
   
PostPosted: Fri Apr 10, 2020 9:05 pm 
Offline
Turbo Slant 6
User avatar

Joined: Mon Jan 25, 2010 11:29 pm
Posts: 644
Location: Seattle, WA
Car Model: 75 Dart SE (2),75 Swinger, 74 Dart Sport,91 Ram RV
(Idle fuel adjustment.) My first & easiest step. Then I go deeper, as these other gents are directing. :)

_________________
"Louise", a 1976 Dart Custom project, (now sadly reverted to being just an "organ donor" to our other project Darts.)


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 7 posts ] 

All times are UTC-07:00


Who is online

Users browsing this forum: Bing [Bot], Google [Bot] and 24 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Limited