I am kind of embarrassed, but I am also at my wits end. Seems simple enough since I have a 66 Ford with a 240 engine. Anyway, original problem was rough running. The carb was leaking, so I purchased a new one, planning on rebuilding my original as time permits. Now, I go down the road, and everything is fine until I hit about 45MPH. I step on the gas to get up the hill and it just starts jerking. If I let up on the gas without a load it will cruise along. I pulled the distributor and replaced points, condensor, rotor. Cap, plugs and wires are new. Timing is on. It has good vacuum, and compression is acceptable. I guess the carb is the culprit even though it has been replaced? Any other ideas? Oh, I did change the fuel pump also.
Tommy
When you changed the fuel pump, did you check for adequate fuel supply? Could be the tank pickup tube is clogged or a line to the fuel pump is collapsed etc.
Have you reved it with the breather off and watched the vac gauge and choke assembly ?
If it's running fine till you step on it.. My guess is it's choke related. Remove the breather (if app) and wire the choke open to be sure then run it. Just my.02
I did check fuel pressure, but not volume. Fuel pressure was good on the old pump, so I thought maybe volume was low, but I didn't actually check it. It seems that without a load, just sitting in the drive way I can rev it up with no problems. It has a manual choke, and it is open all the way. It still seems to run rough at idle also. Very frustrating.
Tommy
I just thought of something else. Should there be pressure at the fuel line to the carb after sitting overnight? I went to remove the fuel line from the carb, and it sprayed out like I just shut it down, but it had sat all night.
Last edited by tommyleea : 04-16-2008 at 11:29 AM.
Reason: add info
This sounds sort of similar to the issues I was having a couple weeks ago. One thing that really helped me, after reading a post on the site here, was advancing the timing slightly over what the manual said.
Check your choke and idle adjustments as well. Mine used to never run without some choke, but now it purrs even idling at stop signs etc.
Check the accelerator pump, I did a carb rebuild on mine years back and it had a bad hesitation. Took it to older mech and he said I put the accel. pump in backwards. Any way it fixed it.
It sounds like a fuel supply problem. Check all hoses back to the tank.
Generally, if it runs out OK in first and starts missing at lower and lower revs as you go up in gears , it's likely the fuel pump (or bad line).
Consider that 1965/66 F100/350's all had manual chokes, and the original style fuel pumps have fuel fiters in them.
There are two types of fuel filters: paper cartridge type, and the type with a ceramic filter inside a glass bowl.
The glass bowled fuel filter should be mounted to the pump or adjacent, but it and any fuel lines never should be mounted near the exhaust manifold...that'll cause vapor lock.
When was the last time the cartridge type paper or ceramic fuel fiter was changed?
Most ppl don't know it's there, so they rarely get changed, if ever.
There are five (5 !) different fuel pumps used on 240 engines alone: 1965/66.
Early or late production (before/after serial # 844,001) makes a difference, Carter ID numbers on the old ones, must be matched in some cases.
There are three different carbs used on 1965/66 F100/350's: Holley 1V / Ford 1V / Carter 1V.
__________________ Bill / Retired Ford Parts Manager ~ 1962/1997.
Part Number Research: Trucks: 1928/2002 / Cars: 1928/2003.
1965 F100 Styleside Pickup / 390 w/Borg Warner T-85N 3 Speed Overdrive / Original owner.
Consider that 1965/66 F100/350's all had manual chokes, and the original style fuel pumps have fuel fiters in them.
There are two types of fuel filters: paper cartridge type, and the type with a ceramic filter inside a glass bowl.
The glass bowled fuel filter should be mounted to the pump or adjacent, but it and any fuel lines never should be mounted near the exhaust manifold...that'll cause vapor lock.
When was the last time the cartridge type paper or ceramic fuel fiter was changed?
Most ppl don't know it's there, so they rarely get changed, if ever.
There are five (5 !) different fuel pumps used on 240 engines alone: 1965/66.
Early or late production (before/after serial # 844,001) makes a difference, Carter ID numbers on the old ones, must be matched in some cases.
There are three different carbs used on 1965/66 F100/350's: Holley 1V / Ford 1V / Carter 1V.
I have the Ford carb, C5TF-G. I don't have the dash pot for slower idle return. I see on my rebuild instructions that there could be a total of four steel balls. I don't have the dashpot, so that makes three. Then it states that the discharge check ball is for 223 and 262 engines, so that would make two, which is what I have. Does this sound correct? I replaced the fuel pump. My original pump didn't have the filter on it, but the new one does.
Tommy
Last edited by tommyleea : 04-17-2008 at 09:23 AM.
Reason: add info
My vacuum line screws directly into the side of the carb (1bbl). Is this OK, or do I need to get a fitting for the carb, and screw the line into the fitting. It has been this way for several years, but just curious. Thanks.
I have the Ford carb, C5TF-G. I don't have the dash pot for slower idle return. I see on my rebuild instructions that there could be a total of four steel balls. I don't have the dashpot, so that makes three. Then it states that the discharge check ball is for 223 and 262 engines, so that would make two, which is what I have. Does this sound correct? I replaced the fuel pump. My original pump didn't have the filter on it, but the new one does.
Tommy
C5TF-G = Ford 1V Carburetor
1964/72 Ford Truck Parts Catalog / Section 95 / Parts List 8C = no dashpot is called for with this carb (C5TF-G).
Carb Kit: C8OZ-9A586-D (Motorcraft CT-207-D)
There are over 20 different carbs similar to this one used on 1965/72 240 & 300 engines, so don't assume anything in what the carb rebuilding kit sez.
And...
Similar carbs were also used on 144, 170, 200, 223 and 262 engines, which means there could be over 200 ( ! ) different carbs from 1962 thru 1974 using the same carb kit.
While a vacuum line fitting is shown in the carb illustration (section 95/page 3), there is no fitting used for the vacuum line on this carb according to the carb parts list.
__________________ Bill / Retired Ford Parts Manager ~ 1962/1997.
Part Number Research: Trucks: 1928/2002 / Cars: 1928/2003.
1965 F100 Styleside Pickup / 390 w/Borg Warner T-85N 3 Speed Overdrive / Original owner.
1964/72 Ford Truck Parts Catalog / Section 95 / Parts List 8C = no dashpot is called for with this carb (C5TF-G).
Carb Kit: C8OZ-9A586-D (Motorcraft CT-207-D)
There are over 20 different carbs similar to this one used on 1965/72 240 & 300 engines, so don't assume anything in what the carb rebuilding kit sez.
And...
Similar carbs were also used on 144, 170, 200, 223 and 262 engines, which means there could be over 200 ( ! ) different carbs from 1962 thru 1974 using the same carb kit.
While a vacuum line fitting is shown in the carb illustration (section 95/page 3), there is no fitting used for the vacuum line on this carb according to the carb parts list.
