JD 4200 fuel injector pump problem

[gimmodog]

My JD 4200 has sat for a couple of yrs and now when I tried starting it it has no fuel coming out of the injector pump. It ran fine when I parked it. It has the Yanmar 3TNE78A-JT42 3 cyl engine. I do not think this is an air problem. I have installed an electric fuel pump so I know it is getting good fuel pressure to the injector pump without air and it is a self priming engine (which I know works because I have ran it out of fuel before and it primed itself). I took off the shutoff solenoid and found that the lever it controls inside the injector pump only moves maybe 1/16". Since I also have a running JD 4300 I took the solenoid off it to compare and the lever on it moved about 1/4". The 4300 would run with the shutoff solenoid off but this one (the 4200) will still not get any fuel out of the injector pump (the lines to the injectors have been removed for troubleshooting). would anyone know if 1/16" movement is enough to open the fuel shutoff inside the pump. I have read somewhere in my research about delivery valves possibly being clogged. I am assuming that these are the top section where the injector lines connect (the grey area of the picture of the top). My question about the delivery valves is "are they removable without causing any problems" in order make sure they are clean and operable. I did fill the delivery valves orifices with a diesel supplement and it did NOT drain down so I am assuming all 3 are in the closed position (again I assume they open and close), also there was no fuel in the lines to the injectors when I removed them. Other than air in lines this is the first problem I have had with fuel delivery therefore I am a novice with injector pump problems. There is what looks like a cover on the side of the pump that I am not sure if I should remove to have a look inside or not. Is it ok to remove this cover to get a view of the inside? I have attached pics of the pump. Any help would be appreciated.

 

[thepumpguysc]

Yes its ok to remove the cover, BUT.. those screws are VERY tight & you need a hand impact driver, a hammer & a small Phillips head bit.
NO NEED to pull the side cover tho..in most cases.
Just reach in w/ "something" & push & pull on the control rack WHILE SOMEONE cranks the engine..
The fuel coming in, will probably lube the stuck plungers..
Seeing it moves "some" is a good sign.. DONT just keep pulling on it while its stationary.. The fuel & parts have to be moving inside inorder for it to free-up.. So crank the engine while doing it..
Good luck & post back once you get it running..

 

[gimmodog]

Yes its ok to remove the cover, BUT.. those screws are VERY tight & you need a hand impact driver, a hammer & a small Phillips head bit.
NO NEED to pull the side cover tho..in most cases.
Just reach in w/ "something" & push & pull on the control rack WHILE SOMEONE cranks the engine..
The fuel coming in, will probably lube the stuck plungers..
Seeing it moves "some" is a good sign.. DONT just keep pulling on it while its stationary.. The fuel & parts have to be moving inside inorder for it to free-up.. So crank the engine while doing it..
Good luck & post back once you get it running..

I have the impact. would it help to take the cover off and shoot the internals with some penetrating oil? gonna try pushing and pulling first. What do you think about clogged delivery valves is that a possibility and can they be removed without damaging anything?


I pushed and pulling for a good 20-30 minutes, new battery now cranking slow, will pull on it some more after it charges some. seems like it may be moving a little more but that may just be my imagination and wishful thinking. I did notice that it moves less while cranking doesn't seem to spring back while cranking, stop cranking and will spring back but still not much which is puzzling to me.

I got the lever to move more but still not sure if it is opening up or not.

 

[gimmodog]

Next I'm going to take off the side cover and have a look see inside it and take off the delivery valves. If they are clean and not sticking then I am at a loss. all the time it was cranking the diesel supplement I poured into the valve orifices did not drain down. This could be that it is still in the shutoff position

 

[thepumpguysc]

Wow.. it sounds like those plungers are stuck good..
Go ahead & take off the side cover.. you'll get a better idea of how things work..
The deliv, valves are spring loaded shut.. your not gonna get anything down thru the top..

 

[gimmodog]

found this video from a thread about a JD 4600. Does the Yanmar 4200 pump shutoff work the same way? VID 219 1821 - YouTube

 

[thepumpguysc]

Yes.. you see those "things" moving back & forth?? They're call "segments" they are connected to the pumping plungers..
.. they move side to side while the camshaft moves the plungers up & down to pump fuel.
The side to side action is controlling HOW MUCH fuel goes out..
DO NOT loosen the screws on the segments!! EVER.. They control the equal delivery between cylinders & you need a teststand to get them set.
You'll probably find the culprit cylinder/ers when you remove the cover.. the stuck ones will be stuck "up"..
I DONT recommend hammering them down.. the metal inside isn't very strong & things start to break quite easily..
Its best to keep lubing & working the rack or prying lightly on the segments.. and bumping the engine over a few rotations.. so the pump cam can get into diff. positions..
See how THAT works out for ya & if nothing happens we can go deeper.. DONT go unscrewing anything willey nilley.. theres a smart/proper way to fix this.. but if you do, you can get into trouble QUICK,{$$$}

 

[Egon]

On the 4200 the fuel solenoid activates the injector pump pistons. It does not function as a fuel shutoff.

Do you get a nice loud click when the key is turned on?

 

[gimmodog]

solenoid functions as it should. it has been removed until I get it running. there must be something inside of the pump stuck causing the pump to think it is still in the shutoff position.

I am working on it outside and it is raining off and on so may not get to do much today

 

[thepumpguysc]

The solenoid pushes the control rack, which turns the segments, which turns the pumping plungers, so it doesn't PUMP any fuel..
The solenoid doesn't actually turn off the fuel.. SOME machines have a solenoid in the fuel inlet line, that actually shuts off the fuel going TO the injection pump.. BUT we're not talking about them..