I have a B7300 tractor with a D722 engine. I just had my engine rebuilt by a machine shop that the local Kubota dealer uses. I put the tractor back together and when I started the engine it went to full throttle and I couldn't shut it off. I shut off the fuel supply to stop the engine. Both the throttle lever and shut off lever had no effect. Any ideas what to do next?
Problem with b7300 engine need help
- Thread starter pescadorjm
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North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
You have a problem with the injector pump.
Double check the linkage and the return springs on the injector.
If pulling the stop on the injector pump will not shut it off there is something not connected internally.
Double check the linkage and the return springs on the injector.
If pulling the stop on the injector pump will not shut it off there is something not connected internally.
I was thinking it was the return too. I took out the the injector pump to look and the springs are there but I'm not sure if they are connected correctly on injector pump end. They are on the control lever end. Does anyone know of a photo or drawing that shows the springs connected correctly?
North Idaho Wolfman
Moderator
Staff member
Lifetime Member
Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
If yours has the 2 springs one inside the other then smaller attaches to the body of the injector pump and the other larger attaches to the rack pulling it forward.
I finally have the B7300 engine running properly and installed in the tractor. I wanted to post what was discovered to be the problem so maybe someone else can learn from my experience with this.
The engine, with only 122 hours developed a problem, not sure what or why. The previous owner hired a local mechanic to fix it. The mechanic took the injectors out, the injector pump, the timing gear cover, and various other parts. It was determined by the mechanic that the injector pump was bad so the owner bought a new injector pump and new injectors. In the mean time the mechanic left town and the tractor sat with the engine partially disassembled and the injectors out for 5 years. The owner had covered the tractor with a tarp but over the years the tarp rotted and the owners goats ate the rest. So the whole tractor was exposed to the elements. Rain got into the cylinders. When I bought the tractor the owner gave me the new injector pump and new injectors. Still wraped and in the box. After assembling the engine and putting Marvel Mystery Oil in the cylinders I got it to turn over but it would not run. I took the engine apart and found pitting in the cylinder bores, all the piston rings siezed, and the valves covered in crude and not getting a seal. I took the engine to a machine shop that does work for the local Kubota dealer and they rebuilt the engine. The pitting in two of the cylinder bores was too deep to hone out and use oversize pistons and rings. The machine shop bored out the cylinders and installed sleeves. Using the original standard size pistons with new rings. When I put the engine back in the tractor and started it for the first time it went to full throttle and wouldn't shut off. I was able to kill the engine by shutting off the fuel. I had to take the engine back out of the tractor and return it to the machine shop. They installed new springs in the control levers, there's two, one small one inside a larger one. This didn't change anything. As it was a "new" injector pump they had ruled out any problem with the pump. After talking to everyone and trying everything they could think of they took the injector pump out and sent it to a shop that specializes in deisel injector pumps and had them go through it. It was found that something inside the pump was stuck and not moving correctly. When the injector pump was put back in the engine it ran and worked as it should. The machine shop would have had the injector pump checked much sooner but when I told them it was new and still in the box before I installed it they assumed the problem was somewhere else. Even though the injector pump was still in the box when I got it. The pump was purchased 5 years earlier when the tractor first developed a problem. Final lesson learned, don't assume a part is working properly just because it is still in the box and has never been used.
I now have the tractor competely assembled and running. I put the FEL on yesterday and discovered all the hydralic hoses leak. Which was no suprise as the hoses that go from the control to the engine where bad as well. I discovered they leaked when I first started the engine and it went to full throttle. Before I could shut the engine down it sprayed oil everywhere.
Sorry to go so long with this story but when I was searching for information on this forum I wished several other posts had gone into more detail or posted the results of their problem.
The engine, with only 122 hours developed a problem, not sure what or why. The previous owner hired a local mechanic to fix it. The mechanic took the injectors out, the injector pump, the timing gear cover, and various other parts. It was determined by the mechanic that the injector pump was bad so the owner bought a new injector pump and new injectors. In the mean time the mechanic left town and the tractor sat with the engine partially disassembled and the injectors out for 5 years. The owner had covered the tractor with a tarp but over the years the tarp rotted and the owners goats ate the rest. So the whole tractor was exposed to the elements. Rain got into the cylinders. When I bought the tractor the owner gave me the new injector pump and new injectors. Still wraped and in the box. After assembling the engine and putting Marvel Mystery Oil in the cylinders I got it to turn over but it would not run. I took the engine apart and found pitting in the cylinder bores, all the piston rings siezed, and the valves covered in crude and not getting a seal. I took the engine to a machine shop that does work for the local Kubota dealer and they rebuilt the engine. The pitting in two of the cylinder bores was too deep to hone out and use oversize pistons and rings. The machine shop bored out the cylinders and installed sleeves. Using the original standard size pistons with new rings. When I put the engine back in the tractor and started it for the first time it went to full throttle and wouldn't shut off. I was able to kill the engine by shutting off the fuel. I had to take the engine back out of the tractor and return it to the machine shop. They installed new springs in the control levers, there's two, one small one inside a larger one. This didn't change anything. As it was a "new" injector pump they had ruled out any problem with the pump. After talking to everyone and trying everything they could think of they took the injector pump out and sent it to a shop that specializes in deisel injector pumps and had them go through it. It was found that something inside the pump was stuck and not moving correctly. When the injector pump was put back in the engine it ran and worked as it should. The machine shop would have had the injector pump checked much sooner but when I told them it was new and still in the box before I installed it they assumed the problem was somewhere else. Even though the injector pump was still in the box when I got it. The pump was purchased 5 years earlier when the tractor first developed a problem. Final lesson learned, don't assume a part is working properly just because it is still in the box and has never been used.
I now have the tractor competely assembled and running. I put the FEL on yesterday and discovered all the hydralic hoses leak. Which was no suprise as the hoses that go from the control to the engine where bad as well. I discovered they leaked when I first started the engine and it went to full throttle. Before I could shut the engine down it sprayed oil everywhere.
Sorry to go so long with this story but when I was searching for information on this forum I wished several other posts had gone into more detail or posted the results of their problem.
Great information and glad that you shared it with us. So glad you got back into the seat with it running.........God bless.....Dennis