Stumbling on acceleration
Post Fiend
Joined: Feb 2008
Posts: 5,831
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From: St Albert, Alberta
I agree that’s what the book says and I wish I could make that work but FWIW I couldn’t get a clean idle with the secondaries open. Maybe it’s because the later 4180s like mine only have two idle mixture adjustment screws? I don’t know. I can say the two that I rebuilt both had the secondaries at zero when I took them apart and that’s also where I found my tuning happy place.
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The 4180, 4160, and the Autolite 4100 all only have 2 idle air mixture screws. Secondary idle air is fixed. If you can not get the engine to idle properly with the seconday's set to factory spec's the carb Idle air circuit is not suitable for the application or there are other issues with the carb.
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New User
Joined: Sep 2018
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The stumble or hesitation is from a stop or slow roll. Once at cruising speed, when I floor it , its a brief hesitation. Also wanted to mention that I did replace the fuel filter when I replaced the tune up items. It's the clear "in line" type and the flow when running looks fine. Like I said initially, the truck starts up immediately, runs and idles great, even has a lot of giddy-up once it catches. We'll get this old girl right.
Elder User
Joined: Jul 2015
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after fully warm, find a deserted place, like an empty parking lot. Stomp accelerator to the floor and hold it for until top of 2nd gear. Let us know exactly what it does when you pop throttle open that hard and don't lift. Does it pop? Does it struggle gaining speed? Does it take off burning rubber and run fine when full throttle?
FTE Legend
Joined: Nov 2015
Posts: 30,880
Likes: 4,117
From: Angier, NC
after fully warm, find a deserted place, like an empty parking lot. Stomp accelerator to the floor and hold it for until top of 2nd gear. Let us know exactly what it does when you pop throttle open that hard and don't lift. Does it pop? Does it struggle gaining speed? Does it take off burning rubber and run fine when full throttle?
He is best to pop off the filter lid and give a look see into the carb, motor off, to see if it squirts.
Dave - - - -
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When its cold the throttle response is not as bad but it still has to be a timid acceleration, but it will still pop and die if I just accelerate normally like you would any other car. its a little worse when warm, just more touchy on acceleration. At this time I don't pull out in front of anyone . I need time to play with the pedal. I did look in to the carb and it sprayed pretty good when I throttled it. I'll try the parking lot, but I have a feeling its gonna pop and die. Does start right up though. Other than that, like I said before, once I get it past the stumbling, she takes off and runs perfect. Thanks again to all for helping with this issue.
FTE Legend
Joined: Nov 2015
Posts: 30,880
Likes: 4,117
From: Angier, NC
When its cold the throttle response is not as bad but it still has to be a timid acceleration, but it will still pop and die if I just accelerate normally like you would any other car. its a little worse when warm, just more touchy on acceleration. At this time I don't pull out in front of anyone . I need time to play with the pedal. I did look in to the carb and it sprayed pretty good when I throttled it. I'll try the parking lot, but I have a feeling its gonna pop and die. Does start right up though. Other than that, like I said before, once I get it past the stumbling, she takes off and runs perfect. Thanks again to all for helping with this issue.
I don't know how the pump is set up on that carb, what model is it and is a Holley right? The Holley's I have played with you can change out the pump cam or ramp and the squirters to larger or smaller size.
I find most of the time just going to a larger squirter, 28 is stock, to a 31 is all that is needed.
I still say it is a carb issue and it runs better when cold is because the choke is on and this makes it richer to over come the lean pump shot.
BTW have you checked the timing yet? A little more advance can help but not too much you start to get pining.
Dave ----
Post Fiend
Joined: Feb 2008
Posts: 5,831
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From: St Albert, Alberta
When its cold the throttle response is not as bad but it still has to be a timid acceleration, but it will still pop and die if I just accelerate normally like you would any other car. its a little worse when warm, just more touchy on acceleration. At this time I don't pull out in front of anyone . I need time to play with the pedal. I did look in to the carb and it sprayed pretty good when I throttled it. I'll try the parking lot, but I have a feeling its gonna pop and die. Does start right up though. Other than that, like I said before, once I get it past the stumbling, she takes off and runs perfect. Thanks again to all for helping with this issue.
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New User
Joined: Sep 2018
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I agree. I think its a carb issue. When I get it taken care of, I'll update the progress. Thanks again to you all for your insight and recommendations.
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I finally got around to removing the Holly and noticed that the stock intake is a spread bore. I thought the 351W came with a square bore. I bought a phenolic spacer for installing the new carb,but it is set up for a square bore intake. Will that work or should I order a spread bore spacer. I know there is no such thing as a dumb question, but mine sure sounds like one.
Moderator
Joined: Jan 2001
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From: Virginia
What carb did you get? The stores sell square to spreadbore adapters. People frown on adapters but these seem to work ok, I have used them plenty of times before. I would use some sort of spacer or adapter in place of the EGR plate if that is the type you have. If you mount the carb up were it was with the EGR spacer, it just seems to work better and everything fits better.
Elder User
Joined: Jul 2015
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Ditching EGR depends where you live and if inspections, I guess, as it is an emissions thing. I’ve known guys to make block off plates out of scrap steel to remove egr
Ok, anytime you lean out it’ll pop. Rich won’t pop. Your accelerator pump is likely turned to leather from old age. A pop from a hard start indicates lean. I’m sure if you back out of it quickly and lightly throttle it catches up and moves on out, albeit at a slower and more measured acceleration than you’d prefer.
Ok, anytime you lean out it’ll pop. Rich won’t pop. Your accelerator pump is likely turned to leather from old age. A pop from a hard start indicates lean. I’m sure if you back out of it quickly and lightly throttle it catches up and moves on out, albeit at a slower and more measured acceleration than you’d prefer.
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Thanks for the advice. Oh and btw, my ignorance on thinking the intake was a spread bore. It is a square bore 4 hole. I purchased a 1406 Eddy. For now I have cleaned up the EGR plate and carb base. Also got an aluminum 1" spacer and just test fitted the carb. All linkage lines up and its a perfect fit except for the EFE valve. Just removed it and am going to look for a freeze plug to block the hole as suggested by a member of this forum. That's what it is all about. I wouldn't have thought of that..... Thanks to whoever that is. Once this is all together, I'll see how she's running. If I still have issues, my next step is to purchase a new Eddy intake (non EGR since we don't have state inspections here), then ditch the EGR plate and valve. Just trying to save another 3 to 4 hundred.
Thanks again to all. Will update on this journey.
Thanks again to all. Will update on this journey.
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Okay members.
This is what I did with the help and advice from you all:
Bought an Eddy 1406 and all necessary linkage and adapters for Ford automatic. Cleaned up EGR base plate and carb base, Installed new base gasket. Installed EGR plate. On top of that is a 1" aluminum spacer with an interchangeable square bore open or four hole insert. I opted for the four hole since my intake is that way. Installed the carb and linkage components, had to use 3" 5/16-18 bolts to mount carb, spacer and EGR plate. Couldn't locate any studs long enough locally. Hooked up all vacuum lines and fuel lines.
Grabbed fire extinguisher and cranked her up. Choke worked perfectly. Hit the throttle after a couple minutes and it idled down. Took her for a spin and it accelerates great with no hesitation at all and keeps going until I back off. I can say that this was a success. Thanks to all who chimed in.
This is what I did with the help and advice from you all:
Bought an Eddy 1406 and all necessary linkage and adapters for Ford automatic. Cleaned up EGR base plate and carb base, Installed new base gasket. Installed EGR plate. On top of that is a 1" aluminum spacer with an interchangeable square bore open or four hole insert. I opted for the four hole since my intake is that way. Installed the carb and linkage components, had to use 3" 5/16-18 bolts to mount carb, spacer and EGR plate. Couldn't locate any studs long enough locally. Hooked up all vacuum lines and fuel lines.
Grabbed fire extinguisher and cranked her up. Choke worked perfectly. Hit the throttle after a couple minutes and it idled down. Took her for a spin and it accelerates great with no hesitation at all and keeps going until I back off. I can say that this was a success. Thanks to all who chimed in.
FTE Legend
Joined: Nov 2015
Posts: 30,880
Likes: 4,117
From: Angier, NC
Okay members.
This is what I did with the help and advice from you all:
Bought an Eddy 1406 and all necessary linkage and adapters for Ford automatic. Cleaned up EGR base plate and carb base, Installed new base gasket. Installed EGR plate. On top of that is a 1" aluminum spacer with an interchangeable square bore open or four hole insert. I opted for the four hole since my intake is that way. Installed the carb and linkage components, had to use 3" 5/16-18 bolts to mount carb, spacer and EGR plate. Couldn't locate any studs long enough locally. Hooked up all vacuum lines and fuel lines.
Grabbed fire extinguisher and cranked her up. Choke worked perfectly. Hit the throttle after a couple minutes and it idled down. Took her for a spin and it accelerates great with no hesitation at all and keeps going until I back off. I can say that this was a success. Thanks to all who chimed in.
This is what I did with the help and advice from you all:
Bought an Eddy 1406 and all necessary linkage and adapters for Ford automatic. Cleaned up EGR base plate and carb base, Installed new base gasket. Installed EGR plate. On top of that is a 1" aluminum spacer with an interchangeable square bore open or four hole insert. I opted for the four hole since my intake is that way. Installed the carb and linkage components, had to use 3" 5/16-18 bolts to mount carb, spacer and EGR plate. Couldn't locate any studs long enough locally. Hooked up all vacuum lines and fuel lines.
Grabbed fire extinguisher and cranked her up. Choke worked perfectly. Hit the throttle after a couple minutes and it idled down. Took her for a spin and it accelerates great with no hesitation at all and keeps going until I back off. I can say that this was a success. Thanks to all who chimed in.
The reason is the bolts can bottom out before they tighten down.
You can use all thread rod to make carb studs.
Once you know how long you want the stud(s) thread 2 nuts on the rod and place 1 nut on either of where you need to cut the rod.
Cut the rod and where you made the cut round the end either on the grinder or hand file. After the grinder I hit it with a wire wheel also. Then run the nuts off where the cut was and cleaned up.
They should come right off, do this till you have all the studs you need.
Good to hear you got it running good again and all it took was a new carb LOL
Dave ----