Ford 7700 fuel restriction before Minimic lift pump?

[051]

Ford 7700 4 cylinder. Minimec injector pump. Don't know the year, my brother's tractor and I'm just helping.

Getting good flow of fuel out of the line coming to the bottom of the lift or primer pump. Not getting any fuel at any of the injectors and when I work the primer lever I can tell nothing is happening. Is there a screen in there? I took the return line off on top of the lift pump and there is flow but it is very slow.

The pump was rebuilt and the tractor did run but not like it should. We were playing around with the pump timing and then this happened.

Any suggestions appreciated.
Thanks!

 

[Dieseltech]

Try turning the engine ONE turn and try the hand primer again. SOMETIMES the cam lobe for the supply pump will hold the lever up inside and keep the hand lever from working. Also open throttle about 1/3 and push the retard start button before cranking engine to bleed injector lines faster.

 

[051]

Forgot to mention, my brother did turn the motor and try the pump a few times. Still nothing.
Thanks!

 

[Dieseltech]

Do you get fuel at the block bleed screw while CRANKING engine? If not either injection pump is not turning OR supply pump is not working by the internal lever inside.

 

[051]

OK, I'm going to check that this morning. Have to drive over to my brother's to work on it.
Thanks!

 

[051]

OK, I looked it over and over but I don't see anything that looks like a block bleed screw? I was assuming it would be on the injector pump housing but I didn't see anything that looks like one.

 

[051]

Watching videos now, looks like you may be talking about the plug on top of the filter housing? I think I need to study the route that the fuel takes a little closer. I'm thinking I don't know what I'm doing yet.

 

[051]

OK, I think I found them on youtube. Will check them tomorrow. Pardon my ignorance.

 

[Dieseltech]

The injection pump block bleed screw is just to the right of the pump ID tag. Early models were a bleed bolt that needed loosened to allow air to escape the pump steel block. Later models used a constant bleed orifice with a return line. With the line off and engine cranking, OR using hand primer there MUST be fuel coming out to make sure block always has fuel inside to feed the four pump plungers.

 

[051]

Looking at the pic I have on it, there are two bleed plugs, one on each side of the pump ID tag. Will check it in the morning.
Thanks!

 

[Dieseltech]

Looking at the pic I have on it, there are two bleed plugs, one on each side of the pump ID tag. Will check it in the morning.
Thanks!

Do NOT tamper with the plug LEFT of the tag, it's a breakoff bolt from the factory to be left alone. The RIGHT one is the place to make sure there's fuel at the block. Picture looks like the late type with constant bleed line.

 

[051]

Found the bleed plug, Pump still did not feel right, not getting the resistance it should have. So I took the lift pump off. It works fine off the injector pump.

I think I see the problem. The cam it should run on is too far to the right. (pic in the next post) The pump lever is running on the shaft that the cam lobe is on. I turned the engine over and that part in the middle where the pump arm runs is perfectly round. The cam is to the right? I did not try to move the cam over because it seems to me that if I could move it then it's just a matter of time before this happens again.

Am I looking at this right?
Thanks!

 

[Dieseltech]

Found the bleed plug, Pump still did not feel right, not getting the resistance it should have. So I took the lift pump off. It works fine off the injector pump.

I think I see the problem. The cam it should run on is too far to the right. (pic in the next post) The pump lever is running on the shaft that the cam lobe is on. I turned the engine over and that part in the middle where the pump arm runs is perfectly round. The cam is to the right? I did not try to move the cam over because it seems to me that if I could move it then it's just a matter of time before this happens again.

Am I looking at this right?
Thanks!

The feed pump lever runs BETWEEN the number 2 and 3 plunger lobes. The center IS round, but has a very slight offset that you should see go up/down slightly while cranking engine. Also look closely at the feed pump internal lever, the PIN it pivots on will sometimes wear into the pump housing enough the internal lever can't stroke enough to move the diaphragm, but pump will still work by the hand lever. Only fiz when that happens is to replace the feed pump.

 

[051]

OK, I'm going to ride back over there and look closely.
Thanks!

 

[051]

OK, we did get the air out and good fuel flow to the blead plug on the injector pump. Got it running, but it has not power at all.
Now there is fuel leaking from the bottom of the fitting where the metal lines attach. looks like only the back one or two. See red arrow on the pic. It's a significant leak, not squirting but a steady flow down the side and dripping off the bottom of the pump.

The way these fittings are locked in place makes me think that I can't just tighten this up. Any advice here is appreciated.
Thanks!

 

[Dieseltech]

When leaks show up at the outlet fittings it's time the pump was gone through completely. Those outlets take a special splined socket for removal/replacing. Pump will probably need all gaskets and seals replaced, and governor weight set and back plate too. Cam bearings might be used again depending on if worn badly or not. I just repaired a Ford TW30 pump for the same leaks and governor trouble.

 

[051]

OK. I was worried it would be "not good".
If you do this kind of work would you send me a PM.
Thanks!

 

[nashranch]

Dieseltech will make it right