Notices
Carbureted LSX Forum Carburetors | Carbed Intakes | Carb Tuning Tips for LSX Enthusiasts

Canít get motor to run good at idle

 
Old 02-03-2019, 09:30 PM
  #1  
Teching In
Thread Starter
 
Join Date: Apr 2017
Posts: 42
Default Canít get motor to run good at idle

Have a carbureted 6.0 with a 750 quick fuel. Runs good at start, then start smoking and chocking out at idle. The needle on regulator gauge shakes back and forth. When adjusting the regulator it seems to stop adjusting around 6psi.
chines72 is offline  
Old 02-03-2019, 11:08 PM
  #2  
TECH Senior Member
 
Join Date: Jun 2016
Location: Central Cal.
Posts: 10,181
Default

Sounds like a bad regulator...
G Atsma is offline  
Old 02-04-2019, 05:56 PM
  #3  
Teching In
Thread Starter
 
Join Date: Apr 2017
Posts: 42
Default

I was told to change my return line from -6AN to a 8 or 10 and see if that helps. Iíll be doing that this weekend
chines72 is offline  
Old 02-04-2019, 08:13 PM
  #4  
10 Second Club
 
Doug G's Avatar
 
Join Date: Aug 2010
Location: Harford Co. Maryland
Posts: 3,894
Default

7psi MAX fuel pressure
Make 100% sure the floats are set right
Make sure the IAB's are only maybe 1 turn out
Make sure theres not too much transfer slot showing
With motor off, and fuel pump on, make sure no fuel leaking into intake (bad PV or gasket)

Trying another fuel reg won't hurt either.
Doug G is offline  
Old 02-06-2019, 05:38 AM
  #5  
TECH Junkie
iTrader: (1)
 
Pop N Wood's Avatar
 
Join Date: May 2006
Posts: 3,376
Default

What fuel pump are you running?

If pressure stays around 6 psi with the regulator wide open than that means the return line is too small. A new regulator won't help that. What you are doing is measuring the back pressure of the return line. Make sure the return line has a straight shot, no bends and nice high flow connectors.

i recently switched to an Aeromotive street strip pump and now my AN6 return line isn't big enough. I really should switch back to a normal pump, the aeromotive unit is way too big, but rather than replumb the car I am going to try a variable speed fuel pump controller. May also violate the warranty and adjust the internal pressure regulator on the pump

By the way this might have nothing to do with why your engine runs rough at idle. Carb and timing most likely. In addition to what Doug said check for vacuum leaks. Make sure all cylinders are firing, an IR thermometer is a good check for that.

Is this the first start up? have you cleaned the plugs since building the motor?
Pop N Wood is offline  
Old 02-06-2019, 10:58 AM
  #6  
Teching In
Thread Starter
 
Join Date: Apr 2017
Posts: 42
Default

Yea I have a aeromotive street/strip 140 gph and aeromotive carb regulator. Imma change return line to 8 or 10. And I noticed my fuel level on site glass on carburetor looks way to high. A lil over half. What is the recommend height for float level?? Is it half or lower?? Yes I just put new plugs in but may have to change them again.

Thanks for all the information.

Last edited by chines72; 02-06-2019 at 11:07 AM.
chines72 is offline  
Old 02-06-2019, 07:48 PM
  #7  
10 Second Club
 
Doug G's Avatar
 
Join Date: Aug 2010
Location: Harford Co. Maryland
Posts: 3,894
Default

1/2 to a little less than is good.

I also have the Aeromotive SS pump, -10 (or -12 ?) from cell to pump then -8 all the way to the regulator on to the carb....dead-headed...no issues.
Doug G is offline  
 


Thread Tools
Search this Thread

About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: