My machine has a 4 cylinder kubota engine (bought new/rebuilt motor a few hundred hours ago. Suddenly, it started bogging down and stalling and then chugging and cycling through. It sounds like it’s not getting fuel. (It’s an old Bobcat 7753). Any ideas what things might cause this?
thepumpguysc
Elite Member
Have u tried back blowing the fuel line.?
Take the line from the inj pump, loosen the tank cap & using compressed air, back blow the fuel line..till it bubbles in the tank..
Good luck
Take the line from the inj pump, loosen the tank cap & using compressed air, back blow the fuel line..till it bubbles in the tank..
Good luck
Harry in Ky
Veteran Member
Does the fuel gauge work? How full is the fuel tank? The older Bobcats have the tank under the motor with both supply and return lines in rubber bushings on top of the tank. The supply standpipes have been known to deteriorate and fall apart. when that happens it won't pump fuel properly when the level is at or below any damaged spots on that pipe. You might try adding a little more fuel to see if it makes any difference.
thepumpguysc
Elite Member
Harry is correct..
So listen to the air/bubbles of the air going back to the tank.. if the fuel is low or the inlet pipe has fallen off, you’ll hear air.. if things are good, you’ll hear bubbles.
So listen to the air/bubbles of the air going back to the tank.. if the fuel is low or the inlet pipe has fallen off, you’ll hear air.. if things are good, you’ll hear bubbles.
dodge man
Super Star Member
Fuel filter been changed?
Hay Dude
Epic Contributor
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Kubota? Fuel filter, clean out lines, then maybe injectors.
EddieWalker
Epic Contributor
Most common reason for lack of power is the lack of fuel. I don't know your machine, but in all of mine, there is a main fuel filter and then a screen somewhere that's hidden. It could be just before the fuel pump, part of the fuel pump, or inside the fuel tank. In all 4 tractors, I removed the screen and added an inline fuel filter. Once it starts to happen again, it's cheap and easy to replace the inline fuel filter.
The other thing that it might be is the solenoid the turns off the tractor. When you turn the key off, it closes the fuel supply to the engine, and it stops running. This happened on one of my tractors. I was losing power and struggling to mow uphill. It was fine on flat land, or so I though. But once I got it to open all the way when running, I found that I had a lot more power!!!!!
Vapor lock in the tank is pretty rare. Air in the fuel line is also very rare.
The other thing that it might be is the solenoid the turns off the tractor. When you turn the key off, it closes the fuel supply to the engine, and it stops running. This happened on one of my tractors. I was losing power and struggling to mow uphill. It was fine on flat land, or so I though. But once I got it to open all the way when running, I found that I had a lot more power!!!!!
Vapor lock in the tank is pretty rare. Air in the fuel line is also very rare.
