# Ford 4000 Diesel mid 70's losing fuel prime



## ramdino (Jun 5, 2021)

My Ford 4000 loses fuel prime if it sets for a week or so. Eventually I can get it going by repriming it, but it loses its prime after about an hour of operation. Then I have to start all over again. There seems to be air getting in somewhere because when I open the screw on the injector pump there is some air in the fule there and when I pump the reprime pump below the injector pump there is air there. Of course there is no fuel at the injectors on the head themselves until I get the air out of the system thru the button pump. Just before the engine quits it accelerates like it got a rick mixture or some more fuel and then it starts sputtering. Ideas?


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## Hacke (Feb 22, 2011)

A mid 70's 4000 with a reprime (lift?) pump? Could you post a picture showing the injector pump and prime pump?


Of course there may be air getting in through connections and plugs, but the most common reason to this is that the filter/s is/are not correctly assembled to the filter head.

There should only be one sealing ring at the head ("lid"). It sits in a groove in the head, and the filter's edge seals against it when you tighten the filter. No sealing ring on the filter.

There is another sealing ring in the cup at the bottom.


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## ramdino (Jun 5, 2021)

Ill get a picture, but it is behind a bolt(3/4)? below injector pump/ You remove bolt and there is a spring loaded button you push with the back end of a wrench. It squirts fuel out the back side but also allows air bubbles to come out the front til I get pure fuel. Then I have to crack open the injectors at the head and turn it over til I see more fuel than air bubbles at the injectors and start tightening them down. Usually after I tighten the first one it will start firing and once I do the second she fires off.


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## ramdino (Jun 5, 2021)

Hacke said:


> A mid 70's 4000 with a reprime (lift?) pump? Could you post a picture showing the injector pump and prime pump?
> 
> 
> Of course there may be air getting in through connections and plugs, but the most common reason to this is that the filter/s is/are not correctly assembled to the filter head.
> ...


I found a picture online and the arrow points to the bolt that has the pump behind it.


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## Hacke (Feb 22, 2011)

That is not a priming pump, it is a device for timing advance and should not be tampered with.


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## ramdino (Jun 5, 2021)

Hacke said:


> That is not a priming pump, it is a device for timing advance and should not be tampered with.


So by pumping it have I screwed something up with the timing? It seems to be the only way to get the air out of the system. When I have just bleed the filer, then the injector bleed screw, I cant seem to get fuel to the injectors before the battery dies. when I have pumped on this thing it seems to go much faster getting the air out of the system.


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## Hacke (Feb 22, 2011)

ramdino said:


> So by pumping it have I screwed something up with the timing? It seems to be the only way to get the air out of the system. When I have just bleed the filer, then the injector bleed screw, I cant seem to get fuel to the injectors before the battery dies. when I have pumped on this thing it seems to go much faster getting the air out of the system.


I do not know what can go wrong, perhaps the "rich mixture" and sputtering comes from this. I hope user Thepumpguy reads this and can help.

You get air in the system, check the filter/s first.

Here is an Owner's Manual that shows the proper way to bleed the system:
www.ntractorclub.com/manuals/tractors/Operators%20Manual%20All%20Purpose%20and%20LCG%20Tractors%202000,3000,4000,and%205000.pdf


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## thepumpguysc (Jan 25, 2015)

Lol.!!! THATS HILARIOUS.!!
Replace all rubber lines and olives on the steel lines “to & from” the filter.
Does your on/off valve under the tank leak.?? ANYWHERE IT LEAKS can suck air..
It’s also possible that the inner workings aren’t tight inside the pump and bleeding back.


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## thepumpguysc (Jan 25, 2015)

When it races just before it shuts off is absolutely normal.. don’t give it a second thought.
The only thing u need to do is open the double screw by the name plate and crank the engine.. fuel should squirt a city block w NO AIR.. and tighten..
Now loosen all the steel lines AT THE INJECTORS & crank the engine until fuel squirts out there WITH NO AIR & tighten.. 
Do ALL THIS W THE THROTTLE AT FULL SPEED..and the shut off in the run position..


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## ramdino (Jun 5, 2021)

Hacke said:


> I do not know what can go wrong, perhaps the "rich mixture" and sputtering comes from this. I hope user Thepumpguy reads this and can help.
> 
> You get air in the system, check the filter/s first.
> 
> ...


Much appreciated, blessings.


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## ramdino (Jun 5, 2021)

thepumpguysc said:


> When it races just before it shuts off is absolutely normal.. don’t give it a second thought.
> The only thing u need to do is open the double screw by the name plate and crank the engine.. fuel should squirt a city block w NO AIR.. and tighten..
> Now loosen all the steel lines AT THE INJECTORS & crank the engine until fuel squirts out there WITH NO AIR & tighten..
> Do ALL THIS W THE THROTTLE AT FULL SPEED..and the shut off in the run position..


Ok tks, I've done that several times amd it will crank but runs sometimes for an hour or more and then sometimes for 15 min,typically after it has already been running and shut down. Would the hot engine have anything to do with the shorter time. Water pump is circulating coolant.


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## thepumpguysc (Jan 25, 2015)

It sounding more and more like “floaters” in the fuel tank.??


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## ramdino (Jun 5, 2021)

That might be a point. The screen that is attached to the valve threaded up through the bottom is unattached. It might be rusted amd occasionally drifts over the place where it was attached and causes fuel starvation although I don't see how that would allow air in the system.


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