Ford 4000 vaporlock

bjasa · Apr 8, 2020

Has anybody rerouted the fuel line on a Ford 4000 gas tractor out there? I have to keep the tank full when it is hot or it vapor locks. You literally see bubbles in the small sediment bulb by the carburetor. I do not use ethanol. The fuel line runs from the tank next to the motor by the intake and exhaust manifolds. any help will be appreciated. Thanks Bob in N.E. Nebraska

Janicholson · Apr 8, 2020

Today's fuel (meaning the fuel you purchase in Spring 2020) is Winter blended gasoline. It has a formulation with more volitiles. This makes starting easier and customers happy when it is below freezing. The fuel use this winter was normal, but from mid march the glut meand there is still massive stocks of winter fuel in the system.
Putting an aluminum heat shield between the manifold and the fuel line will keep it much cooler. Attach the shield to the engine, not the fuel line. Cutting a rubber hose long ways and fitting it over the line will also help. Jim

Steve@Advance · Apr 8, 2020

With any gravity feed gasser, keep the line as far away from the exhaust as practical without unnecessary bends and loops.

You can add insulation and heat shields.

I like to use the premade steel brake lines. They are easy to form without kinking, come with perfect double flairs. Another advantage of steel, it transfers less heat than copper.

If there are any inline filters, now would be the time to eliminate them. They don't do well with gravity systems, and the fuel sits in the filter longer than just passing through the line, allowing it more time to heat up.

Also check the ignition timing. Retarded timing, non working centrifugal advance, points out of adjustment cause slow timing, which causes the exhaust to run hotter.

730virgil · Apr 8, 2020

I knew of an older man that"borrowed" his wifes spring type clothes pins for his Massey 44 and put them on gas line.
His thinking was clothes pins helped get heat off of gas line.

Steve@Advance · Apr 8, 2020

Virgil, I've seen that done to the old cars.

Never understood how or what it could possibly do, but the lo' times swore by it!

They would also clamp cow magnets to the gas line, 'slpain that one! LOL

Greg1959 · Apr 8, 2020

HTH

JDEM · Apr 8, 2020

I do not understand. If you have a gravity feed gas system, vapor-lock is pretty-much impossible. Maybe you have gas boiling for some reason? Vapor lock is caused by suction from a mechanical fuel pump that lowers the boiling point of gasoline. When the suction gets too high the gas turns to vapor and the fuel pump can not longer draw gasoline from the tank. In your case with gravity feed? There is no suction. I must be missing something here?

Greg1959 · Apr 8, 2020

JDEM, my .02 cents from what I experienced.....with my Ford 860 gasser. I'd run her brush cutting during a hot summer day. She would just quit/shut down. I could hear gas bubbling/gurggling/boiling in the gas tank and see air bubbles being pushed out into my sediment bowl from the fuel line.

I agree with you about the system being gravity fed. All heat shields and fan shroud were in place. I re-routed the fuel line and never had a problem again.

You got any other explanations? I like to hear them.

John T · Apr 8, 2020

I used to have a heck of a time preventing vapor lock on older Ford gas mechanical fuel pump and carb motorhomes with long fuel lines HOWEVER I never had the same (vapor lock) problem on gravity fed (NO fuel pump suction failures DUH) carb tractors. Of course extreme heat in the fuel line (manifold area) or carb area can cause problems. See if you can re route and/or insulate to keep heat away (or transfer to dissipate it) from the gas line may help.

John T

bjasa · Apr 8, 2020

I like Greg's picture for rerouting the fuel line which I will have to do. I do have the same carb and sediment bulb setup as his picture. My fuel line is on the backside of the sediment bulb. I failed to mention I used some aluminum flashing around the gas line from the carb up past the manifolds. Maybe it's making it worse. Yesterday I spread fertilizer with the tractor and I had issues. Again you could see the gas bubbling in the top of the sediment bulb. Than you everyone for your responses.

JK-NY · Apr 8, 2020

I am guessing you are referring to a 4 cylinder 4000 which has the same engine as the 800-900 series Ford . I have a 960 Ford. It is semi-retired now but 25-30 + years ago I did a lot of heavier work with it- baling hay, tillage and running a silo blower. On a hot day usually doing some disking when the gas tank got below half full the gas would boil and have the same effect as vapor lock- tractor quit. I rerouted the fuel line out over the top of the manifold with a section of brake line and it pretty much solved the problem . This was before the E10 gas - I don?t know if the ethanol fuel would be more susceptible to boiling or not.

the tractor vet · Apr 8, 2020

Your missing the heat shield between the tank and valve cover . It is suppose to keep the reflected heat off the bottom of the tank .

Steve@Advance · Apr 8, 2020

One other thing to check, be sure the gas cap is vented.

I have seen the vent clogged with bug nests, even bought a "vented" cap that turned out to not be non-vented.

A trial run with the cap loose will prove the point.

Strange that it would be bubbling in the sediment bowl. That's too far from any heat source to be boiling there. Possibly there is a vacuum in the tank and it's drawing air around the needle valve. Or gas steam pockets rising up the line creating vacuum at the carb. Strange...

Greg1959 · Apr 8, 2020

The tractor vet , my other post on this thread stated...."All heat shields and fan shroud were in place"

Greg1959 · Apr 8, 2020

The tractor vet, Not my picture but, don'tcha think that the paper towel stuffed into the carb intake would be a greater problem, according to your diagnostic analysis of the picture?

RobCons · Apr 8, 2020

My 4 cylinder 4000 has a rubber line routed very similar to the picture and I dont have a problem. I had to replace the intake/exhaust manifold on my 641 with an aftermarket one and then the gas would boil. All sheilds were in place and fuel line was not changed. It was rubber just like the 4000.

Greg1959 · Apr 8, 2020

Steve@Advance, It is strange, but by rerouting my fuel line, it cured the shutting down problem. Wooo-eeee-oooo.

rustyfarmall · Apr 8, 2020

The 800 series and 900 series Fords all had that same problem. It was FORD that came up with a solution. Get the muffler out from under the tank with an exhaust pipe specifically made for that purpose, and then install a vertical muffler. The heat shield is not enough.

JMOR · Apr 8, 2020

(quoted from post at 17:13:46 04/08/20) The tractor vet, Not my picture but, don'tcha think that the paper towel stuffed into the carb intake would be a greater problem, according to your diagnostic analysis of the picture?

hat is just a cheap make-shift air filter! :lol:

Geo-TH,In · Apr 8, 2020

I put a clear inline gas filter on Jubilee. When the gas got to 145 degrees you could see the fuel stopped flowing in filter. Shortly after engine ran out of gas.

Fuel cooled filter would fill with fuel.
The heat from radiation heated the gasoline.

I removed filter and vapor lock when away.
George

Ford 4000 vaporlock

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