crappy throttle response, hesitant

[71-F-250SC-72-F-250C]

When I hit the gas the truck hesitates, does not matter if it has been tuned up or not. It does not really bother me that much, but that just makes alot of people have less faith in the truck. When ever anyone rides in it they say how it sounds like its about to die. Anyway, I have rebuilt the carburator, because I thought it was the accelerator pump and it wasn't. Then I remembered how my dads truck always seemed to hesitate a bit getting out of the hole, so I figured it was just the two barrel. I was just reading a post in cjs_f-250 thread that said it could be the core that could make it run like this? The heater in my truck does not work, it doesnt bother me much b/c in the winter the transmission gets that cab warm, but if it is the core thats causing the truck to run like this I want to replace it. That is one of the last places I would have looked.

Sorry for the long post
Stephen

[flyboy2610]

I have never heard anything like this regarding the heater core. My first thought was the accelerator pump as well. I still lean in that direction.
What carburetor do you have?
When you rebuilt the carb did you put on a new base gasket?

[mcarlson11]

I have a 1965 f250, and my truck does the exact same thing yours does, I also rebuilt the carb, but that didnt help. It only does it starting out, after you get going it runs fine.

I really want to get this fixed, but I dont know whats causing it

[cobraF100]

Check your Timing

[71-F-250SC-72-F-250C]

I have the motorcraft 2 barrel carburator. When I rebuilt it, all the gaskets were replaced and we have checked the timing several times. I asked my dad about the core, and he said that if it were bad, the truck would not even start. So I dont know if me and him were talking about the same thing, but the only core there is I am guessing is the heater core. I can remember my dads truck always doing the same thing, so I am thinking the carb is to small for the engine. Also I think the 67-71 fords had the autolite carbs and the 72s had the motorcraft, although they are exactly the same.

Stephen

['75-4x4guy]

check your vacuum advance . I have a 1967 3902bbl/c6 that has the same hesitation ,turns out that the vacuum advance is torn causing a vacuum leak and a slight hesitation

[Heavenlyfire]

I agree with the vaccuum advance. Also I had the same problem with my 4bbl and it was the plunger on the accelerator pump. One side of it had worn down enough to cause a hesitation. Good luck

[berad357]

On my 360 I disconnected the V/A unit altogether. I am using only centrifical advance with base timing set at 12 BTDC. Run good on regular unleaded.

[Heavenlyfire]

I also had to lean mine out a little and it worked. But mine wasn't real bad.

[GreaseMonkey]

Like almost everyone els says check timing. And you might also check your points in you distributor.
Don

[Jonathan Rickman]

I'd be looking at the vacuum advance as well. Try plugging it and see if the problem goes away. Does it ping at all right after the flat spot? If so, then the vacuum advance could be bringing the timing in a little too quick.

[Lazy Jake]

Stephen,

Your Dad is talking about the *coil*. The heater core has absolutely nothing to do with the way your truck runs. Hesitation will be caused by the *tune* of your engine. Like the other guys said: 1. Check for any vacuum leaks. 2. Check your timing with the vacuum advance line blocked off. 3. Check it again with the vacuum line connected to make sure the vacuum advance is working. It will run without the vacuum advance but, you will pay a price in fuel mileage, and we already do that.

Good luck,

Dale

[cannonball]

your dad was definitely talking about the coil not the core. i don't believe it's the coil or the vacuum advance. the vacuum advance is used at part throttle when cruising. you still have a mechanical advance with the counter weights and the vacuum advance is acheived by an actuator attached to a plate on the base of the distributor which bumps the timing slightly to increase fuel economy. i would suggest the accelerator pump on the carburator. pull the aircleaner (with the engine OFF) and look down the top of the carburator. when you push the throttle back, you should see a squirt of fuel from the jets on top of the carburator down into the motor. this is what gives it it's initial, off-idle, acceleration. hope this helps!!!

[71-F-250SC-72-F-250C]

I have already rebuilt the carb, and replaced the accelerator pump. My dad put a vaccum guage on it, and it was smooth it stayed in one spot. It has been awhile, but for some reason I remember the number 17? It was steady, but the truck still hesitate's and when your crusing at 50 mph it seems to miss. I have just been driving it like it is. We are always adjusting the points on it, which I know is normal, but thats gonna have to go. I can hear a vacuum leak but the gauge say's it is running fine. Tommorow I will check the vaccum again. My dads truck always did hesitate, and we thought it was because the 2 barrel was not enough for the engine. My dad used to work for ford as a mechanic so some of the stuff I am saying may not be exactly what he said. If you guys have a 2 barrel on the same engine and it does not hesitate though, my dad's and my truck have a problem.

Stephen

[cannonball]

could be the condensor on the points going out, missing a charge every now and then. didnt know the carb was already rebuilt. sorry bout that. if it's not just an acceleration problem, and it's doing it going down the road, i would look into the ignition system.