My '65 F100 with I-6 240/3 on tree starts right up, but after a few seconds sputters to a stop. My uncle suggested the ignition coil so I just replaced that to no effect.

If I let it sit for 20 minutes after it dies and then start it, it will run up to a minute before it dies again. That's enough time to drop into gear and get it to move a few yards. If I restart it right away, it will only run a couple of seconds.

Does that sound familiar to anyone?

Battery and starter are strong. Cranks and starts everytime. Either spark is dropping off or fuel is the problem. Initially thought water in gas and used heet. I've since refilled the tank with fresh gasoline.

Is my 1bbl carb shot? Does it sound like low fuel pressure? A friend suggested the accelerating pump, but it does it when I'm not accelerating. Pump action feels fine...motion with noticeable resistence when I move the linkage by hand. I can hear the fuel inside squirting too.

 

If it will pop off and run everytime, but then fall on its face after only seconds of run time....I would look at Fuel pump as an issue....Not sure what pressure it should be running, but A guess would be 4-6 lbs ....if you have access to a fuel pressure tester, plumb it inline near the carb....And have someone fire thew truck up.....Watch the pressure needle while running....it should stay steady with very slight pulsation....if while running it falls flat...I would say diaphram in pump has a hole in it...And after sitting 20 mins it gravity feeds enough fuel to fill the bowl up...allowing your 1-2 min run time, but if you try to fire it off after only secs...it hasn't the push to get the fuel up.....

If it is the issue Stock pump is cheap...or go electric, and by pass it....

Let us know.....John

 

Thanks John. I've got a pressure guage that, if memory serves, has instructions for a fuel pressure test. If I can manage it, I'll post the finds

 

I had a similar problem with a 65 Mustang, it would quit running at totally random times. I messed with coils, float bowl levels, all kinds of fooling around. The solution was to replace the condenser in the distributor. A lot of headache for a $2 part. So for the cost, you might try tossing another condenser in it.

 

i would check that condencer first my 66 240 had the same problem it was a broken wire on the condencer $3 fix the guy i bought the truck could not figure it out and i got a heck of a deal($200) for a straight rust free 66 f100 short bed 240 .

 

I think fuel. Stuck choke, weak fuel pump, pluged filter, clogged exhaust pipe. Pull the coil wire off and hold it near the engine block. Have someone turn the engine over. Do you have a snapping blue spark that knocks the paint off the block or a wimpy yellow one? Disconnect the fuel line at the carburetor stick it in a bottel and have someone turn the engine over. Should have lots of gas.

 

Crud in the fuel system. Engine starts, runs, begins pulling crap from the tank into the filter. Filter clogs, shuts engine off. Engine off, no pressure from pump, debris falls off filter or away from tank pickup. Rinse, repeat.

This happened with a Nissan pickup I bought with a rusty fuel tank. I could make it down the road about 5 houses before it would quit. It got progressively worst the more you tried to run it. Let it sit for awhile, and you could repeat the process.

 

I had the same problem on my 66 F100 with the 240, and my problem was the fuel cap wasnt on right when I got it, and alot of water mixed with the fuel, made lots of rust in the tank, and it would plug the line from the tank. Filters and everything looked good, and had a heck of a time figuring out what it was. Actually, found it because the fuel gauge always said 1/4 full, so I decided to take a look, and the float was rusted through and filling with fuel.

 

Partially clogged fuel filter would be my guess, and if the pump is the original type, there's a screw on tomato juice sized can on the outside of the pump that contains the cartridge fuel filter.

It rarely gets changed because most peeps have no klew it's there.

The filter is still available from Ford (and autoparts stores under the Motorcraft number).

C4AZ9365B .. Fuel Filter-Cartridge Type (Motorcraft FG1A)

 

I had lots of garbage in my fuel system when I first bought my '65. My solution was to add a second clear fuel filter in line before the factory filter so that I can see when it's plugged or full of water, etc.

Your problem does sound like fuel issues to me as well.

 

FWIW , i had the same problem, ended up being a piece of plastic in the fuel tank about one in. round. it would suck up to the pipe and the truck would die. i agree with these guys, you have a fuel blockage. the next time it dies remove the gasline line at the carborator and if there is no gas there then go backwards, if you have gas there then you have something in the neddle and seat or in the bowl itself. Dutch

 

Been following the this thread, you mention you have a feul pump tester. Most of them the gauges reads pressure and vacuum. Use this tester to analyse your fuel system and find or eliminate the fuel system as your problem. First do a pressure test on the pump outlet, while cranking the engine it should go up to 4 to 7 pounds and hold that pressure with no visable drop for a while. Next do a vacuum test on the pumps inlet or suction side. Again crank engine over until max suction is reached and it should hold that vacuum with no visable drop on the gauge. If these two test hold you know the inlet and outlet checkvalves and diaphragm are in good shape and the pump is good. Next put a tee on the suction line a the pump inlet, start the engine and run it, the vacuum should be zero. watch the gauge as the engine runs, let it run till engine quits or stalls. If that gauge gives you a vauum reading there is an obstruction in the line or tank and you then need to find it to fix problem. The gauge stays at zero and the engine quits you know its not the pump. Next get can of gas and rubber sution hose long enough to hook to the inlet/suction side of the pump and put the hose in the can of gas, start and run the truck. If it keeps running and don't quit, you have a pin hole in a hose or the steel line that runs along the frame or the suction tube in the tank. Finally I've had this happen, if this truck has sat for a number of years with old gas in it and not been run, the steel suction line in the tank rusted and flaked at the fuel level. Filled the tank up and the truck ran perfect, but when the level in the tank got down to the rusted hole in the line it started errratic an would quit. These checks will tell you if it is a fuel problem from the pump back. Do these checks first and if all fine then look elsewhere for prob. This reply is long enough. Let us know after you've done these and more suggestions can be sent your way. Good luck

 

Sorry, in the line where I said put a tee into the suction line I forgot to say hook the tester to the tee

 

Sounds like fuel problem. Hose in the gas can is a good test as stated earlier. Another good thing about the 240, is that you can take the top off the carb and check out the innerds with it running. Does it run longer with the choke on? I put a new carb on my 240, and had the same problem you are having. I took the top off the carb, and found out my choke was sticking intermittently. It would let gas in, then when it raised up the sides of the float would rub on the bowl and stick in the up or closed position. When the bowl was empty, the truck would quit. I squeezed the sides of the float together, and it has run like a champ ever since. Not that this is your problem, but just something to keep in the back of your mind. It drove me crazy for many weeks. Cheers.

TommyJ

 

See if you can rule out a few things; try this. Get a small plastic gas can with fresh gas; get a section of rubber fuel line and run this directly to the inlet side of your fuel pump, and shove the other end into the gas can below the level of the fuel (you may have to prime the line by getting a siphon started). Plug the line coming from your fuel tank with a golf tee or if you're at the rubber flex hose, clamp it off with vice grips so that it doesn't leak all over the place. See if the truck will idle with this set up, and if it does it points to a problem with your fuel, your fuel tank, or the line between the tank and the fuel pump.