WD6 Won't switch to diesel

bbcandyman

New User
My son has a WD6 that starts fine on gas but dies when switching over to diesel. The first try each time almost starts and then each time after that doesn't fire at all. It is stored at a show grounds so only gets started a couple times each year. 2 years ago it ran great. Last year we were having trouble so opened the petcock on the main filter and it spit a bunch of crap out and then started. It ran for quite a while and then died and wouldn't go to diesel again.
With all that in mind, he changed both diesel filters, oil and filter and drained and filled the coolant this year. We have tried getting all the air out through the petcocks on the filters, injectors and by the bowl but problems continue. I read on someone's post about pulling it for an extended time. We pulled it for a short time and had some smoke coming out but never heard it fire.
We are looking at selling it so any advice or estimated value would be greatly appreciated.
 
It helps to place a value on it if we know where you live. If I was 20 years younger, I would be interested in it.
 
Warm it on Gasoline then pull it. White smoke is a good sign, warm for 10 minutes!! Is there fuel pressure on the gauge! If the white smoke can be made to go from
little to lots with the throttle lever it should run. If no joy, the rack may be stuck in the pump. Jim
 
Thanks for the feedback. We are located in NW Minnesota.

I don't believe the pressure gauge works but when running on gas, if I open the petcock on the main filter, I get diesel coming out. Originally it was lots of bubbles but now is just fuel. Nothing comes out of the auxiliary filter petcock.
When pulling it, the smoke didn't seem to change when I moved the throttle. We were pulling it with too light of a tractor. Next time we will be using a Case LA that should pull a lot better. The other thing it would do when pulling it was after a few minutes it would pop out of gear and we would have to stop and start again.
I don't know a lot about tractors and especially diesel. My father-in-law rebuilt it about 20 years ago but the diesel always worked for him so he isn't a lot of help. He just keeps saying "just keep trying...it will go".
 
If you are trying to start it in 5th gear, it will test that gear's integrity, use 4th. and pull it at about 4 MPH. Jim
 
all depends on what u mean by some smoke,... if its smoking white like a freight train that's good. if not then the rack is stuck. exactly
what a stuck rack will do when switching to diesel . i have had a few tractors like this. and i am presuming u have it properly bleed when
running on gas. and your last two sentences in the first paragraph dont make sense to me.
 
I was pulling it in 3rd gear. Hoping to get out there tomorrow to try again and we will give 4th a try. There was very little smoke coming out when we pulled before.
When running on gas, if I open the petcock of the primary filter diesel fuel comes out. If I open the petcock on the other filter nothing comes out. Not sure if that proves fuel flow or not.
 
It should flow between the filters. Make sure there is a half tank of fuel. It should not pop out of third, but that is a heavy tillage gear and may have seen
serious use. Jim
 
well from what u say ... you are not bled then. thats why it wont start. you bleed the primary first by gravity, then start on gas and bleed
the secondary ,.. it will be spraying diesel all over!
 
Did a little googling on the stuck rack in the pump and looks like a big project. Is there any way of testing to see if that is the issue?
 
The filler hole for oil looks down on it. Wiggle and tiggle and maybe it will free. It would move with the throttle lever if free. Jim
 
Pull the tappet cover and watch the change over valves. See it they move or not. They do stick in the open position this will not let them switchomover and stay running. They they are what changes the size of the combustion chamber from gas to diesel.
 
I agree with others. It's sounds like the
rack is stuck in the pump. The fuel
pressure gauge only gives a reading from
the transfer pump. You could still have
good pressure on the gauge with a rack
that's stuck.
 
This is the pump we are talking about, correct?

Is the plate with the large A on it the tappet cover and can it be removed with the 4 bolts?

If stuck, what is the best way to get it moving again?
 
mvphoto97461.jpg
 
I think you are a little confused about how the tractor
reacts when pulling it. If you are going to shift the WD6
from 3rd to 4th when pulling the engine is going to
turn slower in 4th. Maybe the thinking is that it will not
pop out of gear. This is one of the few times I will
disagree with JANicholson you will not harm 5th gear
by pull starting. The gears are designed to handle full
torque of the running engine. Just pulling the tractor
against engine compression will not come close to
straining the gear train as the running engine.
However, avoid quickly letting out the clutch this can
strain things just as it does when you do it with a
running engine. All this dragging it around will do
nothing towards making it run non diesel if the rack is
stuck. Maybe a very, very slight possibility it will work
the rack loose. Another thing that has not been
mentioned is there is a set of small valves that open to
expose the spark plug chamber to combustion gases
so it can run on gas to warm up. When you switch to
diesel these valves have to close to reduce the
combustion chamber volume and raise the
compression ratio to fire the diesel fuel. If the engine
continues to run when you switch it over and is not
making the usual knocking sound associated with a
cylinder firing on atomized fuel from the injector there
is likely a problem with the switch over mechanisms
that control those valves. It also closes a set of
butterflies in the intake to close of the gas/air fuel mix
and should shut off the spark ignition. If you send me
an email I will provide you some links to helpful
reference material.
 
disconnect the throttle lever from the pump. if the lever has little movement the rack is stuck.
 
and if its stuck you remove the oil filler cover spout. then you can get in thee with a tiny punch and Lightly tap the horizontal adjusting bolt forward.
 
NO, what is that going to do. i said unbolt the oil fill spout on the INJECTION PUMP. it has 2 1/4 inch bolts. the injection pump holds one
pint of engine oil also and has a check plug at the bottom.
 
I have also seen recommendations of soaking down with denatured alcohol and letting it sit for a day. Thoughts?

What kind of oil should be run in the pump? Might as well drain and fill with new oil while I am at it.
 
For clarification (and possible reputation defense :) My reference to pulling in gear was in thinking he had it in 5th, and that the reason it popped out was the abuse 5th gets. I also suggested that the popping out of 3rd could be due to it being a tillage gear and may have wear more than others, causing jumping out. Jim
 
This brings up another question. Do you normally pull start in the highest gear? My father-in-law's go to has always been 3rd gear.
 
3rd or 4th are OK, and, when pulled at about 4 to 5 mph with a capable tractor, will turn above idle
speed. this (in a warmed up Gas start diesel) will allow starting with the engine speed lever
advanced to 1/2 throttle or so. Too low a gear or too fast could drag the tires, or overspeed the
engine. Jim
 
yes that is the oil fill spout, remove it to see if he rack is moving while someone operates the throttle. you should see the horizontal
little adjusting bolt moving back and forth as the throttle is moved . but as i said disconnect it at the pump then you can do it as a one
man operation as i said in the first place.thing is when given info run out there and do as requested then come back and report not all this
jumping around from thing to thing. and yes change the pump oil drain at the bottom. and yes same oil as the engine uses.the information is
only good if your going to follow through with it. i hate typing stories for the heck of it.
 
Sorry for the confusion. I was trying to post a video while I was out working on it. Hopefully it will work now.
[video play=false:3cf5d7cf49]https://forums.yesterdaystractors.com/videos/mvvideo97481.mp4[/video:3cf5d7cf49]
 
Tried it again tonight and fuel ran out of the primary filter even when not running as someone said it should. When running it would only drip out of the auxiliary filter. Pressure gauge showed high pressure except when I had the petcock of the auxiliary filter open which makes sense.

Am I back to pulling it around?
 
I think there should be substantial flow at the second filter. It might be plugged up. But giving it a tug around the farm won't hurt as long as there is some
fuel getting to the pump. Jim
 
The rack is the threaded part at the top
of the screen. It should move with the
other two and doesn't look like it is.
 
Yeah that threaded part didn't move at all. The other part moved a little ways and then sprung back.

I got my hands on a parts manual and service manual. I am pretty sure we have the wrong filter on the aux side. I wasn't there when my son put them in but I am pretty sure he had the same filter for the final and aux. Obviously that should be corrected but would it stop flow?

I will try to get back out there in a couple days and see if I can get the rack to move.

Thanks again for all the assistance.
 
Finally got back out there to work on the WD6. Using some PB Blaster and a screw driver, I was able to get the rack to move. I was able to get it to move with throttle and then it would slowly slide back. If felt like it was still sticky and hopefully will move freely after soaking a bit. Is that how it should work?

Still no fire when I tried flipping it to diesel.

Found out my father-in-law has another pump that he said wouldn't work on it but at least I can open that one up and see what is inside so I have a better idea of what is going on.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top