Carb (4350) help
Thread Starter
|
Senior User
Joined: Apr 2012
Posts: 335
Likes: 0
From: San Diego, CA
Carb (4350) help
Hey guys, rebuilt the 4350 over the weekend, as outlined by FMC400 and others disassemble soak in chem dip, spray off with carb cleaner, blow out with compressed air, settings to spec, and everything went reasonably well. Set the air/fuel mixture with vacuum gauge holding right between 19-20, started and idled better seemed more responsive getting pretty happy with myself. Went for a test drive everything looking good punch it and hear the great sound of secondaries opening. Then does not idle back down, get it back in the driveway, barely, and do some checking around. After a bit I figure out that after the secondaries open and the idle races if I open the air valve plate by hand idle immediately drops down, if I pull it open all the way it dies.
Can someone explain the way the air valve plate works? Should it be opening on it's own? The linkage is as it was and matches all the research I can find I figure it must be something internal that I did not do correctly but I suppose it could be some linkage issue?
Any thoughts appreciated, I have to go to work but will check back later to see if anyone has any ideas.
Thanks!
Can someone explain the way the air valve plate works? Should it be opening on it's own? The linkage is as it was and matches all the research I can find I figure it must be something internal that I did not do correctly but I suppose it could be some linkage issue?
Any thoughts appreciated, I have to go to work but will check back later to see if anyone has any ideas.
Thanks!
Thread Starter
|
Senior User
Joined: Apr 2012
Posts: 335
Likes: 0
From: San Diego, CA
Can anyone help me with some carb mechanics? Would it make sense that the problem may be that the secondaries are sticking and idle goes down when air valve plate is opened because of added air not because the plate isn't functioning properly?
If I can understand the theory behind the pieces I wil have a better chance of fixing this issue as well as future ones.
Thanks
If I can understand the theory behind the pieces I wil have a better chance of fixing this issue as well as future ones.
Thanks
Thread Starter
|
Senior User
Joined: Apr 2012
Posts: 335
Likes: 0
From: San Diego, CA
Before I tested it the second time I backed the high idle screw way out to make sure it was not hanging up. Also quick blip on the throttle like I would do after warming a bit to get the idle down did nothing.
Has been raining all day here hopefully tomorrow I can pull it off and take a look for anything obvious. Let me know if you have any ideas.
Thanks
Cargo Master
Joined: May 2009
Posts: 2,587
Likes: 47
From: Eagle River, AK
I have a 4350 in my 76 that needs a rebuild too. From what I have read, the 4350 is a problematic carb, but it should still run ok, just not great.
Not sure if I want to go through the hassle of swapping out the intake to a standard square bore carb or not. I have an Autolite 4100 I could drop on it if I did that though.
Not sure if I want to go through the hassle of swapping out the intake to a standard square bore carb or not. I have an Autolite 4100 I could drop on it if I did that though.
More Turbo
Joined: Oct 2011
Posts: 636
Likes: 5
From: down a red dirt road
mine from my 74 460 gave me a lot of trouble. mostly in the tuning of the fast idle with all the parts and cams between the carb and choke housing. mine would idle real fast so i would slow it down by loosening the choke thermostat housing and turning it so the choke plate backs off. sometimes it kept it further shut if just a hair too much. try backing it off cold and test. (this way it holds it open)
i never could get my float adjusted correctly. that engine would idle and put around pretty good, but trying to punch the throttle made it fall on its face. the accelerator pump wasnt working correctly causing most of that.
i never could get my float adjusted correctly. that engine would idle and put around pretty good, but trying to punch the throttle made it fall on its face. the accelerator pump wasnt working correctly causing most of that.
Thread Starter
|
Senior User
Joined: Apr 2012
Posts: 335
Likes: 0
From: San Diego, CA
I am lucky it does not get real cold so I was able to get the heat choke to work pretty well. Actually in hindsight it was running ok even with out the accelerator pump working, but I wanted to fix it before it got worse, serves me right I guess.
i will be looking at another solution down the road also but right now I have to work with what I have.
Also have California smog to worry about so might try and go with an early square bore and maybe an older holley to look stock, will have to see but whatever it's down on the priority list.
Did have one bit of luck, at the pick an pull looking for carb parts an I found the drivers side battery tray I have been looking for
gotta be a bright spot in there somewhere!
right now it's still raining, got a cold one in hand, everything else can wait tell tomorow.
i will be looking at another solution down the road also but right now I have to work with what I have.
Also have California smog to worry about so might try and go with an early square bore and maybe an older holley to look stock, will have to see but whatever it's down on the priority list.
Did have one bit of luck, at the pick an pull looking for carb parts an I found the drivers side battery tray I have been looking for
gotta be a bright spot in there somewhere!right now it's still raining, got a cold one in hand, everything else can wait tell tomorow.
Trending Topics
Thread Starter
|
Senior User
Joined: Apr 2012
Posts: 335
Likes: 0
From: San Diego, CA
Pulled the carb back off today and went through disassembly, carb cleaner, air , re-checked the internal settings( all were okay) and got it back on. Should be happy as the secondaries seem to work properly and it idles back down. Seems to take a lot of movement on the mixture screws to affect vacuum and then I can only hold 16-17 and that is erratic. Maybe a vacuum leak? I don’t know, done for now, at least it will be back on the road.
Might be as good as I can get out of this thing. Has anybody used a spread bore to square adapter rather than change manifolds?
Might be as good as I can get out of this thing. Has anybody used a spread bore to square adapter rather than change manifolds?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Cargo Master
Joined: May 2009
Posts: 2,587
Likes: 47
From: Eagle River, AK
I have not used one, but when I was researching it for my truck, the Trans-Dapt 2199 is the only one out there that seems to work for these.
They are spendy, but still cheaper than a manifold.
Trans-Dapt 2199 Carb Adptr 460 Ford : Amazon.com : Automotive
They are spendy, but still cheaper than a manifold.
Trans-Dapt 2199 Carb Adptr 460 Ford : Amazon.com : Automotive
Thread
Thread Starter
Forum
Replies
Last Post
Scorcher21
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
4
Apr 14, 2016 07:16 PM
Jason316
1987 - 1996 F150 & Larger F-Series Trucks
3
Mar 20, 2010 09:09 PM
PaulzF150
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
5
Dec 7, 2009 04:19 PM