1965 Ford 1 ton not running correctly

old

Well-known Member
So I am trying to get this old 1 ton back up and in good working order. It will run but I have to have the coke pulled most of the way out or it dies. With it this way it seems to not want to take gas when you try to throttle up. If you sort of feather the throttle it will rev up but not well. I am thinking that maybe it is the vacuum brake booster and if it is bad it might cause a intake vacuum problem. Brakes have not worked on it in decades. I'm think about unhooking the host at the manifold and capping it off to see if that helps. By the way I did rebuild the carb about a year ago and it has run this same way since doing that plus before I did the carb rebuild.

Any body have any ideas on this. Ford 1 ton 300 straight 6 with a one barrel carb
Thanks
 
The fuel supply is adequate or it would not help for long to choke it. A vacuum leak does seem likely. Or stuck PCV Jim
 
what year is it? If it has a one barrel carb it is probably 60's.

Yes, the first thing to do is plug the brake booster line. It also sounds like the carburetor has trash or sediment in it. What make carburetor does it have?

Is there a carburetor bowl drain? You need to check to see if there is adequate fuel flow to the carburetor by opening the drain to see if gas flows out when cranking. This is especially true if you have to pull the choke out all the way. If you rebuilt it, it does not mean everything in the carb is right. The float level may not be correct. or there may be an air leak where the carburetor top and bottom pieces fit. (warpage) The first thing to check on the carb is fuel level in the bowl and fuel flow to the bowl.

1. Failing fuel pump diaphragm.
2. Bad fuel
3. Clogged jets.
4. Sticking float
5. Dirty air filter
6. Float/needle sticking or dirty.
7. old or clogged fuel filter even if new from sediment or water in the tank.
8. Gas cap not venting. Loosen it a little while trying to crank.
 
Changed the fuel filter at the same time I rebuilt the carb. If I pull the fuel line off the carb and spin the engine over I have a good flow of gas out of the line.
 
I was wondering if maybe the PCV could do that also. I think I will pull the spark plugs and look them over also since who know when they where replaced last. And at the very least clean the plugs. So I guess after eating lunch I'll cap off bot h vacuum hoses and see if that make a difference
 
Old,
You replied while I was writing. You may have good fuel flow to the carb, but that does not mean the bowl is filling fast enough or is at the right level.
 
The subject lien give you the year as in 1965!!
#1 I've pull the line off the carb and spun it over and have a good gas flow out of it. #2 I have put in 10 gal of fresh gas so fuel should be ok
#3 Air filets is the old oil type filter and it runs the same with it on or off.
#4Gas tank venting has been check and I have run it with the gas cap off no difference in how it runs
#5 fuel filter is almost new and it has not ben run more then 5 miles if that since it was put on.

But yes I plan to try capping off the 2 vacuum lines and see it that helps and also pull the air cleaner off at the same time so as to make it easier to mess with. Might even pull the main jet adjustment screw and spray some carb cleaner in and see if that helps
 
When I rebuilt the carb I made sure the float was set correctly and was working. I can hear or move when flipping carb upside down and right side up again.
 
Sound's like engine is running way lean.If no vacuum leaks carb probably plugged with sheet.
 
If all of this checks out then check the points/gap, dwell, and condition.
A bad capacitor or corroded points can also do this. You cannot even trust new capacitors. There has been rash of new ones that come defective. If this checks out then look at the coil.
 
Points are also almost new. Now days I do not change condenser due to have so many bad right out of the box. Spark is a good blue/white and jumps a 1/4 inch plus gap.

One thing I like about this forum one can use you guys as a sounding board for idea of what maybe the problem
 
It does have a PCV sits to the back of the valve cover about center of it side to side.

Guess that says when Ford added the PCV then if a 1964 did not have but a 65 did
 
Try going around base of carb, spraying carb cleaner at the mateing surfaces. If there is a vacuum lrak you will hear a change in the running of the engine.
 
Most of the Ford straight 300s I've worked on run as smooth as a sewing machine. Sure you haven't sucked an intake gasket?
 
I would connect a vacuum gauge to the manifold to confirm it has poor vacuum. If yes then start searching for massive vacuum leaks. Capping off the connection to the vacuum booster would be the next thing to check. If no, rebuild the carburetor spray again.
 
All carbs must have a device that squirts raw gasoline into the intake anytime the throttle moves Fto open. That is because the air rushes in faster then gas and it takes a moment for the carb to catch up. So the accelerator pump is used to make up the difference. It is near always operated via a soft cup or diaphragm that gets hard and stops working. First thing to go in an old carb.

GM used cups most often and Ford and Holley used diaphragms.

EASY to check. Just look down into the carb when you move the throttle to open and see if you can see raw liquid gas squirting. If not, the pump is not working.

Not sure if you have the Ford or the Holley carb. Easy fix either way.

Note that tractor carbs often do not have accelerator pumps because tractors do not get driven like cars and trucks do. That said, some IH and Deere tractors DO have carbs with accel pumps.
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As I have said I rebuilt the carb and it is new. It will not run at all unless it is choked. If you open up the choke after it is started it dies and will not fire up with out being choked. Cold or warmed up.
 
Already tried that with no change. Capping off the 2 vacuum lines did help a little bit but no much
 
This one does run smooth but only if it is choked about 3/4 of the way. I sprayed carb cleaner around the manifold and carb etc with little if any change
 
Accelerator jump diaphragm was new when I rebuilt the carb about 6 or so months ago. When you pump the gas pedal it sprays raw gas in so it for sure is not that. It will not run at all with out being choked which is where the problem is so not sure what or why it does not get enough gas. Only one adjustment on the carb which is close to where it bolts on the manifold so likely to be the idea needle
 
Brand new or old, one backfire will rupture many a accelerator pump diaphragm.

From what has been stated, fuel is not getting to or thru the carb via the "normal way".

Passage(s) blocked by debris or improper gasket(s)?

10 gallons of good gas is still just 10gallons of good gas on top of old crappy and watery gas.

Fuel flow good when not connected to carb.........ok, how about when connected, does flow go to near zero?

Is there a screen at carb inlet, inside carb casting?
 
My bet is on the carb... after reading everything else... main jets stopped up, economizer valve bad or something in the carb.. should be a motocraft carb iirc...
 
No screen or filter at the carb it self. As for old gas it only had a small amount in it since I try to make sure I park things with little to nothing in the tanks.

As for back fire this thing has never done that and I have checked that the accelerator pump does in fact work
 
Old,

Do you have a propane torch?

If you do valve take the unlit torch open the valve wide open and move the tip around the intake manifold to see if the rpms pick up.

If this has no effect move the tip to the intake to see if the rpms pick up. You may have to idle it up a little until it stumbles a little before you put the tip to the intake. If you have to take the air cleaner off make sure you have a fire extinguisher handy just in case. Sometimes the torch head has to be removed to provide more propane.
 
I haven't owned a propane torch for over 2 decades. Spraying the carb cleaner around pretty much does the same thing as the propane torch does and it had no effect on how it ran. If you look at my other post on this you will see what I have found as I am trouble shooting it
 
I say either bad gas , carb or vacuum leak or bad fuel pump . Most likely carb . My 1991 S15 did the same thing when fuel pump was going bad . My pump was electric and yours should be manual / mechanical unless you have replaced it with an electric one .

Whizkid
 
Gas flow out of the pump is very good and will fill a pint jar real fast. Mechanical pump by the way with the fuel filter mounted right on the pump it self
 
Old,

It looks like you have checked each part three times or more. It is unfortunate that you do not have a spare carburetor to swap out and eliminate it at one swell foop.

The following are checks I thought of but discounted as unlikely or you probably already checked.

A. Failing coil no. You don't have Lucas coil which will do this.

B. Mixed up plug wires. No. It does not backfire and you triple checked it out by observing rotor direction and cylinder position by checking the valves to see if they were in exhaust or intake mode or closed.

C. Timing not too far advanced. No. You checked it and the vacuum advance by disconnecting it with the engine running and trying to speed the engine up. Timing light checked all this out.

D. Bad plugs? No. You did not put Champions in it. They sometimes come defective. Rare, but I have seen it.

E. Bad distributor cap. no. There is no carbon tracking and the rotor strip is not too far from the studs. The carbon button on cap shows signs that it is contacting the brass strip on the rotor.

F. Blocked exhaust pipe. No. You checked it to make sure it was not restricted or dead rat in the pipe. Engine does not sound like exhaust blocked.

That is all I have without being there.

DL
 
Why do you say that. A bad condenser will kill spark and well it runs so it has good spark
 
Well the plugs are old as in decades old. Shoot O'Reilly's could not even find the Champ plug number to math them up to a set of NGK. Champs in it now are RF11YC. I have a set of NGK WR5/2438 plugs I am going to put in.
Coil is the stock coil and well if it was going bad I would not think it would run at all or at least not very long.
Plug wires have not been mess with other then to check 3 of the plugs and did them one at a time so no way to mix them up
Timing has not been touched in decades so not likely.
Cap while it old I would not think it would run as well as it does if it was bad.
Exhaust I checked yesterday while running and it had a nice hot push you hand off it coming out
 
Old,

See, That is why I said you had probably already checked the remaining as unlikely and no they weren't the problem.

Although I admit I did think you might have old Champion plugs, but they probably aren't the problem. I have seen them fail, but not in the manner that is causing the current problem. It would be my luck they somehow are and I end up with egg on my face. lol

They might need regapping and cleaning, but again, not likely the problem.
 
Why replace any plugs if your getting good spark as you say when bad condenser is suggested?

If it runs when choked, it will run when it gets fuel the "normal" way.
 
The 3 RF11YC plugs I pulled out had the correct brown color to them so that says there firing correctly. I have no idea how old they are and could well be 25 plus year old. I know the newer champs do not hold up as well but that is how it is now days.

But yep mostly to be a carb problem
 
Double07,

Depends on where Old checked the spark. If he checked it by testing the high tension lead from the coil and got a good spark it does not necessarily mean he would consistently get a good spark at all of the plugs.
I have a clip on by pass unit made from an old Toyota hybrid unit. It only uses the points in the distributor and bypasses the in house coil and condenser. I hooked it to an old misfiring Jubilee three times and each time it ran fine. When I removed it and restored the regular system it ran like crap. The mechanics said can't be the distributor. They fixed it by adjusting the carb. It ran okay a couple of days then went bad again. Problem was two new condensers. Old said the original condenser was okay. Intermittent failure of a component is a hair puller.

I did have an intermittent failure of a Lucas coil (Prince of Darkness) on an old Jag and it did run like Old's Ford. But his ford does not have a Lucas coil. Hence the joke.

Despite my stories I still think the majority of symptoms indicate the carburetor and if not then somewhere in the fuel system.
 
There is only one non fuel/carburetor possibility left I can think of and again it is highly improbable.
If there is too much of a resistive pathway (corroded electrical fitting somewhere) supplying current to the coil then too little current flows to the points/condenser as the rpm rises. I discount this because of the need to pull the choke to even get it started.
 
Old,

I need to explain. At low rpms you will get a good spark. As the rpms increase there is less rise time for the primary coil voltage/current. So the coil output voltage will drop.

This is rare and highly unlikely in your Ford, but I just mentioned it in passing.
 
(quoted from post at 16:11:55 03/16/18)
Plug wires have not been mess with other then to check 3 of the plugs and did them one at a time so no way to mix them up

So this 300 is a six cylinder but why only check three plugs?
 
Because the first 3 looked good and I was running out of time on that day. Either way I am going to replace them all since I know these plugs are well over a decade old if not 2 or 3 decades old
 

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