7753 bobcat hard start and smokes

[kohlerfarms]

I have a 7753 skid steer with a kobota eng. it has been getting harder to start. It smokes a lot when it first starts. It smokes less after it runs a while. Smoke is like unburned fuel. It also has a miss. When I crack the injector lines open one at a time the motor doesn’t change much on number 4 cyl. I have a lot of crank case smoke also. Any help would be appreciated. Thanks

 

[Tazza]

Sounds like a damaged piston or injector. If the injector has been leaking it can burn a hole in the piston and cause lots of excess crank case smoke.
As you tested to see what pot wasn't too happy, its obviously number 4.
How many hours are up?

 

[kohlerfarms]

Sounds like a damaged piston or injector. If the injector has been leaking it can burn a hole in the piston and cause lots of excess crank case smoke.
As you tested to see what pot wasn't too happy, its obviously number 4.
How many hours are up?

it has 4470 hrs on it. if the exuast smoke goes away would you lean towards a bad injector?

 

[scottie]

It could be a number of things, 7753, 753, 763 injectors have fine tolerances, and are easily damaged by water, first thing and cheapest thing is get injectors checked, it sounds like the injectors are bleeding through overnight which would make starting hard and will blow smoke when running as its not a fine spray and isnt burning properly. If you have a holed piston crankcase pressure will be very high, and will be escaping anywhere it can, eg front and rear crank seals and breather hose will look like a coal train running. A little bit of crankcase pressure is normal for an engine with nearly 5000hrs on it.

 

[Tazza]

It could be a number of things, 7753, 753, 763 injectors have fine tolerances, and are easily damaged by water, first thing and cheapest thing is get injectors checked, it sounds like the injectors are bleeding through overnight which would make starting hard and will blow smoke when running as its not a fine spray and isnt burning properly. If you have a holed piston crankcase pressure will be very high, and will be escaping anywhere it can, eg front and rear crank seals and breather hose will look like a coal train running. A little bit of crankcase pressure is normal for an engine with nearly 5000hrs on it.

I too would start with the injectors, its the easiest and cheapest and at least then you will know they are right.
In the past i have done spray pattern tests by removeing the injectors, attach a tube line to the pump out the back of the machine and install the injector. Crank the engine and watch the spray, it should be a nice narrow cone without any droplets forming on the injector nozzle.
This test only tells what the spray does, not the cracking pressures.

 

[kohlerfarms]

I too would start with the injectors, its the easiest and cheapest and at least then you will know they are right.
In the past i have done spray pattern tests by removeing the injectors, attach a tube line to the pump out the back of the machine and install the injector. Crank the engine and watch the spray, it should be a nice narrow cone without any droplets forming on the injector nozzle.
This test only tells what the spray does, not the cracking pressures.

ok thank you i will start there.

 

[Jyuma]

ok thank you i will start there.

Which Kubota engine do you have? Mine is a V1902 and it is real easy to swap injectors on mine. I would try moving number 4 to one of the other holes and see if the problem moves with it.
Note: If it's anything like mine be careful of those copper washers under the injectors. Some washers stick to the injector and others stick to the head. It's real easy to miss that little fact... ask me how I know.

 

[kohlerfarms]

Which Kubota engine do you have? Mine is a V1902 and it is real easy to swap injectors on mine. I would try moving number 4 to one of the other holes and see if the problem moves with it.
Note: If it's anything like mine be careful of those copper washers under the injectors. Some washers stick to the injector and others stick to the head. It's real easy to miss that little fact... ask me how I know.

i have the v2203. i will try that thx