D950 fueling issue

[Pete G]

Hi all,
I have a sailboat with a Universal Westerbeke MX-25. It's also the Kubota D950, just stuck in a sailboat instead of a tractor. I am having a fueling issue. I'm getting fuel from the low-pressure fuel pump, but the high pressure pump isn't sending fuel to the fuel rail. I replaced the bleed valve (was broken) and I can get fuel flow to the by pass line.

My assumption was that the high pressure pump needed to be rebuilt. I replaced it with a rebuilt unit, but I'm still not getting fuel through the fuel injectors feeds. I bled the engine at the fuel filter - boat folks indicated that it was air trapped in the fueling system, but still didn't run. I replaced the batteries, and it turns over easily, but won't fire up.

Suggestions, nearby mechanics both appreciated.

Pete in Cleveland

 

[North Idaho Wolfman]

When you replaced the pump did you reuse all the shims under the old pump?
Those shims set timing.

When you reinstalled the pump did you make sure to align the rack pin with the governor slot?

You will not normally get fuel to flow out the bypass off the injectors on these engines.

I would first remove the injector lines from the pump and the injectors.
Set throttle to high, crank the engine, you should get 2 to 3 inch fountains of fuel out of the delivery valves.
If that is good, then reinstall the injector lines, but leave them loose on the injector side and crank again till you you get good fuel in little spurts without bubbles, tighten and it should run.

 

[Pete G]

When you replaced the pump did you reuse all the shims under the old pump?
Those shims set timing.

When you reinstalled the pump did you make sure to align the rack pin with the governor slot?

You will not normally get fuel to flow out the bypass off the injectors on these engines.

I would first remove the injector lines from the pump and the injectors
Set throttle to high, crank the engine, you should get 2 to 3 inch fountains of fuel out of the delivery valves.
If that is good, then reinstall the injector lines, but leave them loose on the injector side and crank again till you you get good fuel in little spurts without bubbles, tighten and it should run.

I did not remove the shims from the old pump, at least to my knowledge. It's on the back floor of my wife's car, so I'll check this evening. There was really no way to not align in the slot.

I'll start with removing the lines. When I swapped out the pump, I did remove the lines and blow air through them.

The boat is in a yard on Lake Erie (outdoors), so getting to it this weekend will depend on the weather.

Pete

 

[North Idaho Wolfman]

I did not remove the shims from the old pump, at least to my knowledge. It's on the back floor of my wife's car, so I'll check this evening. There was really no way to not align in the slot.

I'll start with removing the lines. When I swapped out the pump, I did remove the lines and blow air through them.

The boat is in a yard on Lake Erie (outdoors), so getting to it this weekend will depend on the weather.

Pete

In the back seat of the wife's car! If i did that to my wife's car she would kill me!

If you didn't install the shims with the new pump, it is imperative that you do that first, as that is critical for it to run.

When you install the pump you need to pull the stop lever cover off the side to align the pump rack pin to the governor slot.

 

[Pete G]

Thanks. I didn't remove the side panel for the installation - just slid the new pump in. I'll start with tearing it down and removing the pump, etc.

 

[Russell King]

There may be an air bleeding valve on the injector pump. It may look like a bolt screwed into a hew fitting where the fuel line is connected. I really helps on my engine (not same as yours) since it gets air out of the fuel line and fuel filter on my tractor which is gravity fed to the injection pump.

 

[Pete G]

There may be an air bleeding valve on the injector pump. It may look like a bolt screwed into a hew fitting where the fuel line is connected. I really helps on my engine (not same as yours) since it gets air out of the fuel line and fuel filter on my tractor which is gravity fed to the injection pump.

There is. When I attempted to open it, it snapped off. I replaced it, so it's functioning now, and I can get fuel flow to both sides of the bleed valve.

 

[North Idaho Wolfman]

D650,D750,D850,D950, V1100 are all inherently hard to bleed, but it must be done all the way to the top of the injectors.
When I rebuild or work on the fuel systems on these, i go through the extra effort to get all the air out.
If i replace the injectors or pumps, I will run fuel through them before i install them or parts attached to them.

 

[Pete G]

D650,D750,D850,D950, V1100 are all inherently hard to bleed, but it must be done all the way to the top of the injectors.
When I rebuild or work on the fuel systems on these, i go through the extra effort to get all the air out.
If i replace the injectors or pumps, I will run fuel through them before i install them or parts attached to them.

I bled my way from the racor to the engine, then replaced the fuel filter and left it lightly attached, cranked and bled that, then moved up to the bleed valve. Another boat owner (same boat) tried to bleed it, as well, before I replaced the pump. I'll take another pass through it all.

 

[Pete G]

I removed the pump, opened the side observation panel, and made sure everything was aligned. I included the shim and cut a new gasket for the observation port.

No change in the result. ChatGPT tells me the engine needs to be at TDC for this to work - I went by the fuel pump cam lobe closest to the front, so please correct me if I need to remove an injector to find it.

 

[North Idaho Wolfman]

You need to bleed from the injection pump to the Injectors.

Have you done that?

No change in the result. ChatGPT tells me the engine needs to be at TDC for this to work - I went by the fuel pump cam lobe closest to the front, so please correct me if I need to remove an injector to find it.

There is not TDC needed to install the pump, it will work no matter where the engine is at in it's rotation.
The only thing required when you install these pumps is to make sure the pin on the rack gets into the slot on the governor.

 

[Pete G]

You need to bleed from the injection pump to the Injectors.

Have you done that?

I did do that, but I do not get fuel out of the fuel lines. I haven't removed a line completely and cranked it over to see if the lines are all clogged. I blew air through them, so I don't think this is the issue. But, it's my next step will be (if it ever stops raining) just to rule it out.

With the pump removed, when manually turn the engine, I can see the cam rotate, so I know it's not a mechanical issue. The cam shaft looks pristine.

I know the fuel is getting to the high pressure pump, as well.

I have the original, a rebuild kit, and a rebuilt one - Covid supply chain issues.

 

[North Idaho Wolfman]

Take the side cover off and give me some good pic's in there.
If the injection pump is good and your getting fuel to it then the only other thing would be something in the governor linkage or the start spring is missing.

 

[Pete G]

This is the only pic I have right now - will have to tear it down again this weekend. I've also got a borescope if there's something I should be looking for.

From the parts diagram. There was definitely a spring in place that I needed to slide forward to fit the pump, and I had to exert some pressure to insert the pump, so I think the pump is in contact with the cam. Maybe the actual inlet to the pump is blocked? I can pull the pump and run the low pressure pump to see if it fills.