Injector pump and governor

[crazyal]

Does anyone know of a way to test the governor? Lately my 4240 doesn't seam like the governor wants to advance the throttle when the engine starts to bog down. It could be nothing but it might be an issue. I know the fuel system up to the filter is fine and I don't see any change in the smoke (and the air filters are clean) so I don't think there's an issue getting air. But when I rev the motor up to 2800 it seams to be real easy to bog the engine down. Normally I don't need to run that high (2000~2400 rpm range) so I can't say I know what's normal. I did look at the parts diagram so I know approx how the system works. It looks like the throttle is connected to the governor with two springs but I'm not sure how the governor connects to the injection pump. I think it connects to the fuel cam shaft but that part isn't clear. I have been pretty lax about getting the work shop manual but I guess I'll pick one up. Anyway I would rather deal with a potential issue now, in the warmth of summer than in the dead of winter (assuming it has an issue).

 

[Chilly807]

Does anyone know of a way to test the governor? Lately my 4240 doesn't seam like the governor wants to advance the throttle when the engine starts to bog down. It could be nothing but it might be an issue. I know the fuel system up to the filter is fine and I don't see any change in the smoke (and the air filters are clean) so I don't think there's an issue getting air. But when I rev the motor up to 2800 it seams to be real easy to bog the engine down. Normally I don't need to run that high (2000~2400 rpm range) so I can't say I know what's normal. I did look at the parts diagram so I know approx how the system works. It looks like the throttle is connected to the governor with two springs but I'm not sure how the governor connects to the injection pump. I think it connects to the fuel cam shaft but that part isn't clear. I have been pretty lax about getting the work shop manual but I guess I'll pick one up. Anyway I would rather deal with a potential issue now, in the warmth of summer than in the dead of winter (assuming it has an issue).

In a nutshell, the governor controls the fuel rack movement to maintain the engine speed. A set of engine driven flyweights opposes a spring attached to the throttle lever. As load decreases and the engine speed comes up, the flyweight force overcomes that spring pressure and reduces the fuel rack setting. As load increases and engine speed drops, the spring overcomes the reduced flyweight force and increases the fuel rack to bring the speed back up.
It does that at any load from zero to whatever the engine is capable of putting out, less parasitic loads like alternator, A/C, water and hydraulic pumps, etc. They can be tested, but it's not easy. A PTO dynamometer can load the engine to varying degrees, I'd say yours is probably rated at 35-37 PTO HP. A dealer is going to be the only place to find something like that, unfortunately. Unless the engine is in poor condition, which I doubt, they can be pretty bad before they won't develop full HP.

With a mechanical governor there is always some speed droop inherent in the system. In short, there will be a minor decrease in controlled engine speed when you increase load. For example, if you're bush hogging a field and the engine speed is 2400 with the cutter just turning freely, I wouldn't be surprised to see it drop a hundred or more RPM when it's under heavy load, and maintain that speed until the load drops again. If you overload it, the speed will simply decrease until the load decreases or the engine stalls.

I assume your tractor is HST? Does it have the ATA? (Auto Throttle Advance) If it does, that may not be working properly, if at all.

You didn't say what you were doing when you noticed the drop in speed. PTO work or simply moving the tractor? Some of the HST tractors are working hard in the higher speed ranges, I know of one gent with a GL3240 that was surprised at how much the ground speed fell off when climbing a hill in high gear at road speeds. They simply don't have the horsepower to drive that much weight up a hill at that speed.

My gear drive L3400 will run at full governed speed (~2800 rpm or a bit higher) in high gear on a flat road, but throw a hill in front of it and the rpm drops to about 2600. Downshift and the rpm comes right back up as the ground speed drops.

 

[crazyal]

I can dog the engine down without placing too much of a load on it. Trying to go up a moderate hill in M with the H-DS set to slow pulling my grading scraper I can push it far enough so the engine will drop the RPM from 2800 to 1600. I can't get it to stall. I guess my question is this, is there any way to see the if the governor is moving the rack it's full range. As I said I could have reached the end of the usable power and it's acting as expected. I wouldn't think the governor itself was bad as the engine doesn't have a lot of hours on it (250). I'm not sure if it's worth going to a dealer. It sounds like the injection pump would need to be removed to make sure the rack is fully functional.

 

[KennyV]

Your governor can not out perform your manual throttle, but it will be the same as manually moving the throttle... so the next time you have the rpm loosing and you think it is the governor not keeping up, use the manual throttle, if you can get the rpm to recover than it is a governor problem... if it will not recover under the load then it is simply too much load. KennyV

 

[The Fred]

You sound like me griping about my tractor.

I complained to the dealer and they said the lift pump most likely was going bad. I cranked the fuel and all she did was smoke; then came the turbo.:laughing:

You can put a gauge on the lift pump output although I am not sure of the spec. You most likely already tried a new fuel filter?

I have the manual in .pdf form but it is a large file and forget emailing it. You could stop by with a thumb drive you're not far from me.

I'm in Hooterville.

Regards, Fred

 

[wmonroe]

Do the grand L's have a lift pump? I thought they were gravity feed to the injection pump.

 

[Adiredneck]

Do the grand L's have a lift pump? I thought they were gravity feed to the injection pump.

They do. It is after the filter, before the inj pump. I can still see the hoses in my mind because It took a while to route them correctly on my 5240.

 

[crazyal]

I took the filter apart today and found what looks like diesel fuel gel. Clearly it's not below freezing here so that's not what it was. It's possible that it was a clear sticker or tape that had been in the fuel long enough to mostly dissolve. The problem is it was on the outside of the filter, the fuel enters through the inside of the filter so I'm not sure how it could of got there. The filter is about 6 months old. I didn't have a replacement so I reused it for now after checking it over visually and not seeing any issues. I did drain the fuel tank through the filter housing. Nothing came out of the tank, that was good. But when I was wiping things off I found the small o-ring that seals the top of the filter so no crud can get around the filter was breaking down. I'll replace it when I get a new filter, I might even find a better compound (I assume it's viton).

When I put it back together I put an ounce or two of synthetic oil in the bottom of the bowl. Just in case something made it up into the pump a little oil should help lubricate things and try to get it flushed out. I also opened the bleeder for a couple of minutes to make sure any air got bled out of the pump. I did play around with it some and it feels better but it could be all in my head. Usually the tires will break free and spin but where I was the other day that wasn't the case. It's just as possible that unusually good traction made it feel down on power.

It would be nice if Kubota made an easy way to inspect the injector rack movement. If you could then you could also determine the health of the injector pump and possibly the governor. I did talk to a Kubota mechanic (works on refrigerator units) and he said the lift pump is a low pressure unit, maybe 5psi. He said they only go bad due to extreme age (in his opinion). He was told that the shop where he gets his Kubota parts sells them to people who insist that they want to change everything, shotgunning a problem or to people who are cheap and want to replace it before spending big money on an injector pump. If I have any more problems I might remove mine, the fuel lines, injectors and the injector pump so make sure that something didn't make it's way into one of them.

 

[kuboman]

The fuel enters the outside of filter and exits to IP out the center. It sounds like you have algae in the fuel and your problem is a dirty filter. You need to use a good fuel conditioner to keep the algae grown down.

 

[wmonroe]

Do you store fuel in bulk or buy small amounts at a time. If you have a bulk tank looks like you need to put a filter on it and like was already mentioned add a conditioner.

 

[crazyal]

The fuel enters the outside of filter and exits to IP out the center. It sounds like you have algae in the fuel and your problem is a dirty filter. You need to use a good fuel conditioner to keep the algae grown down.

I had assumed that as well but that's not how Kubota plumbed it. It can't be reversed either because the inlet pipe is horizontal while the outlet pipe is vertical. Also the shut off valve is also on the horizontal line.

Do you store fuel in bulk or buy small amounts at a time. If you have a bulk tank looks like you need to put a filter on it and like was already mentioned add a conditioner.

I have it in a 55 gallon drum. This past winter I just switched to a new drum as the one I was using started getting rusty (on the outside) around the bottom bead. I have my heating oil guy fill it when he fills my tanks for the year. My pump has a filter on it so I doubt the drum is causing problems. I usually use it up in about 6 months and then buy it in 5 or 10 gallons at a time. A local gas station just started carrying off road diesel so it's easy to get.

 

[wmonroe]

I have it in a 55 gallon drum. This past winter I just switched to a new drum as the one I was using started getting rusty (on the outside) around the bottom bead. I have my heating oil guy fill it when he fills my tanks for the year. My pump has a filter on it so I doubt the drum is causing problems. I usually use it up in about 6 months and then buy it in 5 or 10 gallons at a time. A local gas station just started carrying off road diesel so it's easy to get.

That isn't long enough to store and have issues with the fuel, especially since you have a filter. I'm at a loss for what could have caused this.

 

[The Fred]

Not any lift pump info or pressure specs in the factory manual at all.

Well Al it's easy enough to drain the fuel tank on your machine and inspect or simply remove it and flush it out with a good detergent and hot hot water.

Castrol Super Clean works very well for this. Then dry using a couple cans of dry gas or alcohol, refit and fill er back up, new fuel filter then you can remove the pump seal and crank yourself OUT one turn on that 6 mm stud at the front of the pump. She'll smoke a little more but might help in the power department.

Your 2.2 liter giant should make around 48 HP. unless you do the real deal like that stupid guy Fred did.

Regards, Donald Trump

 

[kuboman]

What makes you think fuel enters the center of the filter? I have a 5740 and other kubota machines and they all exit out the center of filter. Barrels are notorious for contaminating fuel. Also most hand pump filters are 30+micron which lets enough crud through to plug filters.

 

[The Fred]

I pulled the hose off the lift pump and it free flows a pile of fuel with the engine off, that's going through the filter first.

Then I teed a gauge into the output line and it pulses from 0-6 psi. Hard to get a good reading but it moves fuel for sure.

Regards, Fred

 

[crazyal]

What makes you think fuel enters the center of the filter? I have a 5740 and other kubota machines and they all exit out the center of filter. Barrels are notorious for contaminating fuel. Also most hand pump filters are 30+micron which lets enough crud through to plug filters.

With the fuel bowl off you can easily trace which is the inlet. The fuel shut off in facing the radiator and is in line with the line coming from the tank (as you would expect) and the hole in the center of the housing leading into the center of the filter. The exit route is even easier since the hole is offset away from the engine. Directly above it is the line heading up and over the the lift pump. I don't know why Kubota did this other than to make it difficult to tell if the filter is clean or dirty. Of course it means you should never have to clean the fuel bowl. I have no idea if other Kubotas are done this way.

 

[crazyal]

Not any lift pump info or pressure specs in the factory manual at all.

Well Al it's easy enough to drain the fuel tank on your machine and inspect or simply remove it and flush it out with a good detergent and hot hot water.

Castrol Super Clean works very well for this. Then dry using a couple cans of dry gas or alcohol, refit and fill er back up, new fuel filter then you can remove the pump seal and crank yourself OUT one turn on that 6 mm stud at the front of the pump. She'll smoke a little more but might help in the power department.

Your 2.2 liter giant should make around 48 HP. unless you do the real deal like that stupid guy Fred did.

Regards, Donald Trump

I did drain the tank into two 5 gallon jugs with a clean old shirt as a filter. I didn't flush the tank out because the makeshift filter didn't catch anything. I did look in the tank with a flashlight, didn't see anything.

That was a lot of work to add a turbo to your tractor. It would be fun to do but I have too many other projects that are waiting so I think I would just find a used 5740 with low mileage. The tractor's main purpose is snow blowing. In the summer I'll use it to keep the driveway smooth and drag some trees for firewood. I've got a full sized 580K backhoe for most loader work so I really don't need more power. However id doesn't mean I want to give any up.

 

[David_Kb7uns]

My L3130 flows from the outside in.

If you have a plugged fuel line and a full tank of fuel, sometimes fuel will flow in reverse direction on the fuel filter self bleeding line between filter vent out and the fuel filter vent port on the fuel tank and as the fuel level goes down you loose power. Had it happen on the RTV1100 with water separator kit.

David

 

[ozzie tractor]

ok so for those not paying attention, a governour pulls the throttle to the closed position, while the springs pull the rack to full fuel. so by default if the governour fails, they usually over rev. if a spring fails they usually will not reach max rpm. if the fuel rack is sticky, they hunt (wont hold steady speed). as said, next time its dropping rpm, flatten the foot throttle and see if rpm increases. if not your engine is down on power or overloaded. i also agree that the gloop is bacteria in the fuel and the fuel filters feed from the outside to the inside. drain the fuel, change the filters and add a big shot of fuel treatment is my suggestion

 

[Fallon]

I've never seen a fuel bowl flow from the inside out. The whole point of a bowl is so it will collect sediment & water & that you can see all that junk outside the filter.