The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1960 - 1966 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 03-05-2018, 09:53 AM   #1
65chevysub
Registered User
 
65chevysub's Avatar
 
Join Date: Feb 2013
Location: Cottonwood, Arizona
Posts: 1,373
Engine "lopes" after startup

I have a question about why my engine lopes about 5-10 seconds after startup? It is bad enough that I have to hold my foot on the gas pedal to keep it from dying. Once it has run for a few minutes, it smooths out. I know my carb is running rich. Could that be the problem?
Engine:283
Trans:TH350
Carb: Carter 500 with electric choke
65chevysub is offline   Reply With Quote
Old 03-05-2018, 10:18 AM   #2
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,512
Re: Engine "lopes" after startup

when is your carb running rich? At idle or at cruise?
What’s your idle rpm?
How far open is the choke door just after you start it?
geezer#99 is online now   Reply With Quote
Old 03-05-2018, 01:56 PM   #3
65chevysub
Registered User
 
65chevysub's Avatar
 
Join Date: Feb 2013
Location: Cottonwood, Arizona
Posts: 1,373
Re: Engine "lopes" after startup

It seems rich all the time. Whenever I punch it, I'm getting a bunch of black smoke mostly out of the left side but both pipes are black on the outside.RPM's are about 700. Not sure on how open the choke is
65chevysub is offline   Reply With Quote
Old 03-05-2018, 02:21 PM   #4
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,512
Re: Engine "lopes" after startup

That means you’re flooding likely due to too much fuel pressure or high floats.
Check your floats and lower them 1/8 inch from normal. If that don’t help you’ll need a fuel regulator. Your carb doesn’t like more than 5 psi.
Your choke plate should open about 1/4 inch or slightly more right after it starts up. With a rich carb you might need to open it more. Pull the air cleaner lid off and watch what it does on start up.
geezer#99 is online now   Reply With Quote
Old 03-05-2018, 02:31 PM   #5
jchav62
1962 C-10
 
jchav62's Avatar
 
Join Date: Apr 2005
Location: Las Vegas, New Mexico
Posts: 4,978
Re: Engine "lopes" after startup

Your plugs are probably getting wet with fuel. Takes it a few minutes to burn them clean to smooth the engine out after start up.

x2 on the pressure regulator. Run one on mine. What a difference!
__________________
Joseph Chavez
"See the USA in a Chevrolet!!"
......................_____
.........________//__{\_____
,,,,,,,/__(O)___//___/__(O)_/

1962 C10 Shortbed Fleetside 327/th350 GV overdrive
1974 C10 Longbed Fleetside 350/th350 "The Trash Truck"
1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4
2015 GMC Sierra SLE 1500 4x4
jchav62 is offline   Reply With Quote
Old 03-05-2018, 08:08 PM   #6
65chevysub
Registered User
 
65chevysub's Avatar
 
Join Date: Feb 2013
Location: Cottonwood, Arizona
Posts: 1,373
Re: Engine "lopes" after startup

Thanks guys. I have a pressure regulator. I will put it back on and see if it takes care of the problem.
65chevysub is offline   Reply With Quote
Old 03-05-2018, 11:25 PM   #7
AcampoDave
Registered User
 
AcampoDave's Avatar
 
Join Date: Feb 2013
Location: central California
Posts: 2,726
Re: Engine "lopes" after startup

Btw, running stinking, sooty rich is bad for the valve guides.
AcampoDave is offline   Reply With Quote
Old 03-07-2018, 03:03 PM   #8
65chevysub
Registered User
 
65chevysub's Avatar
 
Join Date: Feb 2013
Location: Cottonwood, Arizona
Posts: 1,373
Re: Engine "lopes" after startup

Ok, got my regulator on but have question. Is the vacuum port right in front of the fuel inlet line supposed to be capped or open? I can't get the picture to upload
65chevysub is offline   Reply With Quote
Old 03-07-2018, 03:09 PM   #9
geezer#99
Registered User
 
geezer#99's Avatar
 
Join Date: Aug 2009
Location: Bowser
Posts: 13,512
Re: Engine "lopes" after startup

Always capped
Any port that nots being used needs to be sealed..
geezer#99 is online now   Reply With Quote
Old 03-07-2018, 04:58 PM   #10
65chevysub
Registered User
 
65chevysub's Avatar
 
Join Date: Feb 2013
Location: Cottonwood, Arizona
Posts: 1,373
Re: Engine "lopes" after startup

Thanks Geezer. I will cap it
65chevysub is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT -4. The time now is 01:31 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com