Hello all,

I have been in the process of getting my 72 F100 running again after sitting down in MS for 3 years. It starts instantly but putters and dies out quick since I can't rec it up from the pedal to the Edelbrock 1406 due to a throttle linkage issue. It has been some time since I've worked on it so forgive my ignorance here, but can any of you please advise as to how to reconnect the linkage plus any red flags you might see in the photo?

Thanks so much
-Chris


Carb area

My grandfather left the linkage looking like this where it was parked

 

Looks to me like your linkage IS connected. The blue rod at the bottom of the throttle lever on the carb is a "pusher" as opposed to the top fitting with the spring wrapped around it being the more common location for a "puller" linkage.
But pusher or puller, they both move the throttle lever the same way.

Maybe the pedal is moving the carburetor's lever, but something is not right with the carb instead. Maybe not enough fuel? Fuel pump issues? They definitely don't like sitting for any length of time once they've been used. They can sit on a shelf dry for years, but once exposed to gasoline they can fail to perform in as little as a few months.

Have you tried dribbling gas, not into the throat, but down the float bowl vents to fill up the float bowl?
Dribbling it into the open venturi only lets the engine run for a couple of seconds. Filling up the float bowl will let it run for a couple of minutes. Sometimes helps an old recalcitrant pump re-prime and start working again.
Sometimes...

What is it that you're feeling when you push the accelerator pedal? Nothing? Maybe it's disconnected down at the pedal itself?
The convoluted cantilever system that Ford used for awhile was finicky and wobbly, but it actually worked pretty well most of the time. Make sure all of your linkages and arms and levers work freely and clean that thing up! Sitting around definitely lets junk build up, but cleaning it can expose a lot of faults and failure points you might not otherwise see.
After a good cleaning, or maybe even before if you are not able to do that right away, would be some good spray-lube into all the joints. To keep rust from proceeding, and to ensure that the linkage moves as freely as it's going to at the moment.

Good pics by the way, though maybe one pulled a little further away from the subject so we can see a broader view of the setup. And maybe a couple of the linkage from where it exits the firewall and including the cantilever setup.
Is the Red wire in the picture of the disconnected plug the same Red wire from the carb's choke?

Good luck.

paul

 

In terms of what I feel when using the gas pedal, it is pretty much floored out and doesn't have any give to it. Couple years back, I remember that the rusted out spring there connected to the carb would have connected to another piece which would have given the pedal some give and it could actually rev the engine up. As it is now though, it is just sitting there and doesn't allow for extra gas to be sent to the carb, only what the fuel pump is sending it.

I haven't drained the tank as of yet, but did end up putting about a gallon or two of gas in there to see if I could get a steady idle without having to go that extra mile. The fuel pump sounds good to me and still pushes gas to the carb. I switched out the old fuel filter next to the carb, and it stays full. I suppose I could check the PSI on the pump with a gauge, will get back with results

The red wire is attached to the carb choke yes, but I remember some years ago we just disconnected the c The truck choke for this application. I had tried a Holley and couldn't get it to run steady before settling on this Edelbrock which proved easy to reassemble. Now though without being able to get the pedal connected properly to the carb or seemingly able to operate the rev manually, could point to other issues. The truck will start instantly in most cases, just peters out. I'm just hypothesizing on that pedal issue plus maybe tweaking the carb richness. Thanks for the help, still working on it all

-Chris

 

Yeah, as good as Holleys are for many things, I sure like the Carter/Edelbrock ease of use and tuning. Popping the top off to take a look-see inside is pretty straightforward and no gas spilling out anywhere.

If the choke is disconnected electrically, then you must hold it fully open somehow. I'm sure it will eventually open up all the way with engine heat, but that might take half of forever as far as the engine's needs are concerned. Better to just lock it fully open so that the associated linkages don't lock the throttle lever in place, or choke off the air from getting into the engine.
A wire tie is probably the easy go-to for this, but we used to use string and rubber bands back when everybody had a box full of those things. Rubber bands did not last forever of course, but lasted long enough so that replacing them did not seem much of a chore.

Once the choke is locked all the way open set the idle speed screw up to the point that it will idle. Then tweak the two idle/air mixture screws while doing it all over until the right balance is achieved. Set the timing too, since advancing the timing typically raises engine speed and retarding ignition timing will lower idle speed.
So set the timing before the final adjustments of the carburetor.

And maybe some more pics of the linkage from carb to firewall? I'm not seeing anything obvious that might do what you're describing.

Paul

 

Once the choke is locked open, any chance of getting some video of the linkage while someone is slowly pressing the gas pedal down all the way?
It might just be that some of the old cantilever linkage is hitting something. Notice all the excess thread showing on the adjuster rods? Maybe it's just out of it's comfort zone.

Paul

 

I am attaching some more pics of the carb setup. I am going to adjust the mixture screws today and see if that gets me any results. As it is the truck peters out shortly after starting with an already weak idle. I haven't lubricated the belts yet either. The pedal does not have any give and is floored out as of right now, so pressing the pedal does not send any extra gas to the carb. That's what has me stuck.

Current linkage setup


Choke current setting

Mixture screws



With choke held open




None of the linkage will move back by hand

 

Then the only thing to do right now is to disconnect all the linkage rods and first look for binding, misalignment or limiting factors, including the act of moving all obstacles out of the way, then lube and adjust it properly.
Re-route that red wire that's not factory and should not be laying on top of the linkage.
Re-route the vacuum hose that runs too close to the linkage too. Probably either for the PCV valve or the brake booster, it should not be there.

The Edelbrock carb is wider than stock and you can see that reflected in the slightly skewed angles on the linkage rods.
And clean all the junk out of the area so you can be sure that nothing is blocking movement. Doesn't look like it from here, but you really should work on a clean setup so you don't miss something from being covered up in leaves and twigs.

Once the linkage is disconnected (including the rod at the main lever back by the firewall) you can then see how the pedal acts and where that rod/lever sits when the pedal is set higher in the cab. You have to have enough travel to open the throttle blades wide, which means either you have to lift the pedal up off the floor a bit, or bend the linkages since they may have been bent already.

Paul

 

2X 1 ton on disconnecting the linkage from the carb. Then adjust the linkage accordingly. This will be easy to do since the head (loop) of the clip which is supposed to hold the rod to the carb's throttle lever is on the wrong side of that throttle lever. The loop should be behind the throttle lever.
Also, I don't see any fuel hose connected to the inlet nipple at the right rear of the carb. Are one of the hoses connected to the front of the carb coming from the fuel pump? Those nipples in the front are both vacuum ports. The bigger one in the middle is for a PCV valve.