Carburetor issue - Ford Truck Enthusiasts Forums

Notices
1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

Carburetor issue

 
  #1  
Old 02-22-2016, 06:47 PM
1987_XLT_Lariat_F250
1987_XLT_Lariat_F250 is offline
Freshman User
Thread Starter
Join Date: Oct 2013
Location: Fayette County, Ohio
Posts: 37
1987_XLT_Lariat_F250 is starting off with a positive reputation.
Carburetor issue

I'm having trouble figuring out what my problem is with the carb. It's a Holley 1850-3, the ignition timing is right, the floats are perfect, and the air/fuel screws are right. I have attached the link to YouTube to watch a video I recorded of it. Thanks! (factory carburetion all EGR items have been removed)

 
  #2  
Old 02-22-2016, 08:54 PM
MI02SVT
MI02SVT is offline
Senior User
Join Date: Dec 2014
Posts: 348
MI02SVT is starting off with a positive reputation.
Sounds like it's starving for fuel have you cleaned it at all

Is the accelerator pump hooked up correctly and working
 
  #3  
Old 02-22-2016, 09:38 PM
Lead Head
Lead Head is offline
Post Fiend
Join Date: Jul 2007
Location: Rhode Island
Posts: 7,857
Lead Head is a name known to allLead Head is a name known to allLead Head is a name known to allLead Head is a name known to allLead Head is a name known to allLead Head is a name known to all
Sounds lean to me too
 
  #4  
Old 02-23-2016, 08:12 AM
1987_XLT_Lariat_F250
1987_XLT_Lariat_F250 is offline
Freshman User
Thread Starter
Join Date: Oct 2013
Location: Fayette County, Ohio
Posts: 37
1987_XLT_Lariat_F250 is starting off with a positive reputation.
I adjusted it to the spec that Holley says in their informal video. When I'm driving it sounds like it has a cold air intake because of all the air it is trying to get.
 
  #5  
Old 02-23-2016, 12:13 PM
Shadow944795's Avatar
Shadow944795
Shadow944795 is offline
Posting Guru
Join Date: Sep 2013
Posts: 1,022
Shadow944795 is starting off with a positive reputation.
Originally Posted by 1987_XLT_Lariat_F250 View Post
I adjusted it to the spec that Holley says in their informal video. When I'm driving it sounds like it has a cold air intake because of all the air it is trying to get.
Check for vacuum leaks. Use a can of brake clean while it is running and spray around this like the base gasket, any vacuum hoses and things like that until you find something. If you don't then let us know and we will go from there.
 
  #6  
Old 02-23-2016, 04:56 PM
1987_XLT_Lariat_F250
1987_XLT_Lariat_F250 is offline
Freshman User
Thread Starter
Join Date: Oct 2013
Location: Fayette County, Ohio
Posts: 37
1987_XLT_Lariat_F250 is starting off with a positive reputation.
The lines and carb base gasket are all good.
 
  #7  
Old 02-23-2016, 05:05 PM
Frozen_Joker
Frozen_Joker is offline
Senior User
Join Date: Sep 2010
Location: Fenton, MO
Posts: 444
Frozen_Joker is starting off with a positive reputation.
It honestly does sound like its starving for fuel. Very odd. Your lines are all clear, all vacuum is good, gaskets are good, carb is adjusted properly. You said you tuned it as per their video. Are you sure their video is specific? Have you tried adjusting it one way or the other to see if that changes anything?
 
  #8  
Old 02-23-2016, 06:25 PM
1987_XLT_Lariat_F250
1987_XLT_Lariat_F250 is offline
Freshman User
Thread Starter
Join Date: Oct 2013
Location: Fayette County, Ohio
Posts: 37
1987_XLT_Lariat_F250 is starting off with a positive reputation.
The EGR stuff was ripped off years ago except the plate and EGR plate itself which was plugged. So I replaced the EGR plate with a carburetor spacer. I'm thinking maybe the accelerator pump might be bad. I can hear squirting if I press on it but I dont understand the issue. The valve covers have 1 a PCV and 2 the oil filler neck on the other has a hole that directs emissions to the breather. The intake has a vacuum port on the back which has one big fitting and two smaller ones. One line is hooked up and is going to the transmission and the other two are plugged. Other than that I'm not sure what else is the issue.
 
  #9  
Old 02-23-2016, 08:48 PM
Shadow944795's Avatar
Shadow944795
Shadow944795 is offline
Posting Guru
Join Date: Sep 2013
Posts: 1,022
Shadow944795 is starting off with a positive reputation.
Originally Posted by 1987_XLT_Lariat_F250 View Post
The EGR stuff was ripped off years ago except the plate and EGR plate itself which was plugged. So I replaced the EGR plate with a carburetor spacer. I'm thinking maybe the accelerator pump might be bad. I can hear squirting if I press on it but I dont understand the issue. The valve covers have 1 a PCV and 2 the oil filler neck on the other has a hole that directs emissions to the breather. The intake has a vacuum port on the back which has one big fitting and two smaller ones. One line is hooked up and is going to the transmission and the other two are plugged. Other than that I'm not sure what else is the issue.
Changed the fuel filter recently? Any major changes or adjustments prior to this? Fuel pump holding decent pressure.
 
  #10  
Old 02-23-2016, 09:07 PM
Tedster9's Avatar
Tedster9
Tedster9 is offline
Post Fiend
Join Date: Apr 2002
Location: Waterloo, Iowa
Posts: 14,817
Tedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputationTedster9 has a superb reputation
With the engine OFF, work throttle while looking down carburetor throat. Should immediately see fuel squirting. This is to prevent the kind of bog or hesitation we're seeing in the video.
 
  #11  
Old 02-23-2016, 09:47 PM
1987_XLT_Lariat_F250
1987_XLT_Lariat_F250 is offline
Freshman User
Thread Starter
Join Date: Oct 2013
Location: Fayette County, Ohio
Posts: 37
1987_XLT_Lariat_F250 is starting off with a positive reputation.
I'll have to check that tomorrow, other than those things nothing else has been done. I'm thinking it may be the air/fuel mixture screws on both sides of the front bowl.
 
  #12  
Old 02-23-2016, 09:53 PM
danr1
danr1 is offline
Post Fiend
Join Date: Aug 2006
Location: Sand Lake, MI
Posts: 5,640
danr1 has a great reputation on FTE.danr1 has a great reputation on FTE.danr1 has a great reputation on FTE.danr1 has a great reputation on FTE.danr1 has a great reputation on FTE.
Originally Posted by 1987_XLT_Lariat_F250 View Post
The EGR stuff was ripped off years ago except the plate and EGR plate itself which was plugged. So I replaced the EGR plate with a carburetor spacer. I'm thinking maybe the accelerator pump might be bad. I can hear squirting if I press on it but I dont understand the issue. The valve covers have 1 a PCV and 2 the oil filler neck on the other has a hole that directs emissions to the breather. The intake has a vacuum port on the back which has one big fitting and two smaller ones. One line is hooked up and is going to the transmission and the other two are plugged. Other than that I'm not sure what else is the issue.
How'd it run before you swapped out the egr plate?

Are you sure your carb spacer is completely blocking egr passage?

Basic type spacers typically did not do so and to prevent doing what you're attempting to do, eliminate EGR's plate/valve. Had to hand create a homemade plate to use in conjunction with a production spacer to be able to block those ports.

If you're not sure might not be a bad idea to check that out make sure all porting is fully blocked off by your carb spacer, no exhaust gas is getting to the engine past it.
 
  #13  
Old 02-24-2016, 09:50 AM
1987_XLT_Lariat_F250
1987_XLT_Lariat_F250 is offline
Freshman User
Thread Starter
Join Date: Oct 2013
Location: Fayette County, Ohio
Posts: 37
1987_XLT_Lariat_F250 is starting off with a positive reputation.
I'll pull it off and do some measurements to check everything.
 
  #14  
Old 02-25-2016, 02:04 PM
Freightrain's Avatar
Freightrain
Freightrain is offline
Shiftoholic
Join Date: Jan 2003
Location: Ohio
Posts: 9,305
Freightrain has much to be proud ofFreightrain has much to be proud ofFreightrain has much to be proud ofFreightrain has much to be proud ofFreightrain has much to be proud ofFreightrain has much to be proud ofFreightrain has much to be proud ofFreightrain has much to be proud ofFreightrain has much to be proud of
Accelerator pump is not doing its job. Will it rev up if you just ease into the throttle? If so, then the accel pump is not getting working properly.

That dead spot is the lean out due to you opening the throttle blades and the vacuum goes low(which means it can't draw fuel in) and that is where the accel pump comes into play. It shoots fuel into the motor to cover up that lean spot.

If you can just slowing rev the motor, then everything else is likely fine. Increasing the throttle slowly still allows the motor to draw fuel as the vacuum signal stays high. It is that sudden open spot that is the issue.

I'm guessing following Holleys recommendations for setting up the accel pump linkage it has too much slop(I never liked how they do it). That arm should not have any freeplay when the throttle is closed. With engine off, grab the arm(where the bolt/spring is at) and see it if moves off the acccel pump arm. If so, then you need to lenthen that bolt just enough that it is just touching it. Not actually pushing on the arm, but just touching. Basically zero lash.

Start it up and try it again.


 
  #15  
Old 02-25-2016, 05:15 PM
1987_XLT_Lariat_F250
1987_XLT_Lariat_F250 is offline
Freshman User
Thread Starter
Join Date: Oct 2013
Location: Fayette County, Ohio
Posts: 37
1987_XLT_Lariat_F250 is starting off with a positive reputation.
I fiddled with that before after watching Holley's video on adjustments. I'll re check it to make sure and in which case that doesn't solve it then I should get a new accelerator pump diaphragm?
 

Thread Tools
Search this Thread
Quick Reply: Carburetor issue


Contact Us 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.