Grain Truck Question

[Howard H.]

Getting my old F700 Ford grain truck (I think it’s a 360 engine) that hasn’t run in several years ready for harvest and it’s not getting fuel to the fuel pump on the engine.

The pump on the engine IS working, but I seem to not be getting fuel from the tank.

Is there an electric loading pump back on the tanks to get fuel to the engine? Or does the engine pump create suction on the tank line to pull it up?


Thanks for any advice,
Howard

 

[rustred]

You could blow back with air on the tank outlet line. Probably the gas is vanished up and stinky and that’s your problem. Even if you have to remove the tank to clean it. Hook up a rubber hose to the fuel pump and stick it in a Jerry can and see if it pumps. Should run that way.

 

[Janicholson]

Several possibilities. A rust hole in a steel line between the tank and pump. A failed rubber line in that position. a failed check valve (intake or exhaust) in the pump. Blockage in that line to the pump.
I would put a rubber line on the pump intake (maybe use a barbed fitting that fits the pump) into a container of fuel then see if it gets fuel.
If yes you know it is rearward from the pump. If none, it could be the pump, or plugged fuel line from the pump to the carb. Jim

 

[Howard H.]

Thanks for the ideas!

 

[Hobo,NC]

Getting my old F700 Ford grain truck (I think it’s a 360 engine) that hasn’t run in several years ready for harvest and it’s not getting fuel to the fuel pump on the engine.

The pump on the engine IS working, but I seem to not be getting fuel from the tank.

Is there an electric loading pump back on the tanks to get fuel to the engine? Or does the engine pump create suction on the tank line to pull it up?


Thanks for any advice,
Howard

A old school vacuum fuel pressure gauge will without a doubt help eliminate the issue. Its important to learn how to test the pickup side this tool will nail down that side easily.

Copy and paste on search "vacuum test mechanical fuel pump" You can waist a lot of time and money guessing no need to guess.

On a mechanical pump you need to check the vacuum on the input side and pressure on the output side. Output should be about 6 p.s.i. and the input(line to tank) should be around 10" of vacuum or higher. You'll need a low pressure fuel gauge and a vacuum gauge.

To check the lines you can use the vacuum gauge and hook it up to one end of the line or filter and plug/pinch off the other end. You can also hook up a short piece of hose to the filter and submerge it in water while plugging off the other end and blowing into it. Same thing with the line but can use soapy water in a spray bottle.

Old rotten fuel lines/hoses will let air in so a good idea to check them. If you aren't sure just replace them. A mechanical pump also needs a good camshaft lobe to move the pump arm enough. One more thing, there's a sock filter in the tank that can get clogged.

 

[cleddy]

A old school vacuum fuel pressure gauge will without a doubt help eliminate the issue. Its important to learn how to test the pickup side this tool will nail down that side easily.

Copy and paste on search "vacuum test mechanical fuel pump" You can waist a lot of time and money guessing no need to guess.

On a mechanical pump you need to check the vacuum on the input side and pressure on the output side. Output should be about 6 p.s.i. and the input(line to tank) should be around 10" of vacuum or higher. You'll need a low pressure fuel gauge and a vacuum gauge.

To check the lines you can use the vacuum gauge and hook it up to one end of the line or filter and plug/pinch off the other end. You can also hook up a short piece of hose to the filter and submerge it in water while plugging off the other end and blowing into it. Same thing with the line but can use soapy water in a spray bottle.

Old rotten fuel lines/hoses will let air in so a good idea to check them. If you aren't sure just replace them. A mechanical pump also needs a good camshaft lobe to move the pump arm enough. One more thing, there's a sock filter in the tank that can get clogged.

I have 2 older pickup(70 Chev & 87 Ford) & truck. Back in the day with every day use they would fire up instantly like the new cars do now even after non-use after a week or so. Now it takes lots of pumping and maybe even priming with a little gas poured in carberator. I get the pressure testing but how long should the lines hold pressure and gasoline? I would use them more if it wasn't so hard to start.

 

[David from Kansas]

Have a '73 chevy C60 with a 366 V8 and if it sits (inside) for more than a week or so it is a little harder to start but with a mechanical choke and a good strong battery, it has never failed to start, even in cold weather. Guess I'm on the lucky side with not having fuel line problems.

 

[KCTractors]

I have a 84 Dodge D350 dump truck that if it sat for a couple of weeks, I always had to dump gas down in the carburetor. I installed an electric pump in it, now turn on the ignition wait maybe 15 to 20 seconds, pull the choke and she will fire up.

 

[Hobo,NC]

I have 2 older pickup(70 Chev & 87 Ford) & truck. Back in the day with every day use they would fire up instantly like the new cars do now even after non-use after a week or so. Now it takes lots of pumping and maybe even priming with a little gas poured in carberator. I get the pressure testing but how long should the lines hold pressure and gasoline? I would use them more if it wasn't so hard to start.

How long it holds pressure are fuel would depend on the health of the fuel system. When you find the answer let us know. No original 40 year old fuel system is in excellent health. I understand the vanishing fuel and cranking it for long periods. In my case coolant flowed through a plate under the carb once I blocked that off the fuel did not evaporate in a week. Fuel in the carb bowl either evaporates are leaks out.

 

[JMOR]

How long it holds pressure are fuel would depend on the health of the fuel system. When you find the answer let us know. No original 40 year old fuel system is in excellent health. I understand the vanishing fuel and cranking it for long periods. In my case coolant flowed through a plate under the carb once I blocked that off the fuel did not evaporate in a week. Fuel in the carb bowl either evaporates are leaks out.

Those old Quadrajets had Welch plugs in bottom that we notorious leak points, so much so that aftermarket made aluminum plugs with grove for o-ring. Bet Hobo has used them.

 

[Hobo,NC]

Those old Quadrajets had Welch plugs in bottom that we notorious leak points, so much so that aftermarket made aluminum plugs with grove for o-ring. Bet Hobo has used them.

I have not I bead blast and apply Permatex loc weld.

 

[Howard H.]

I appreciate all the advice. . I suspected the old nylon fuel lines to the three tanks, but come to find out, a section of steel line inside the frame from the selector switch to the engine fuel pump had rusted a pinhole in it.

I just replaced everything and it starts like a car now!

 

[wore out]

I appreciate all the advice. . I suspected the old nylon fuel lines to the three tanks, but come to find out, a section of steel line inside the frame from the selector switch to the engine fuel pump had rusted a pinhole in it.

I just replaced everything and it starts like a car now!

GOOD JOB! Simple fixes are the best!