Kubota D1105 diagnostic

robdean · Mar 29, 2023

I have an 08 kubota D1105 Generator. I just got it and it was unknown the condition it sat for a long time since it was not needed.

It would not start so i found the injector pump was stuck and it had no fuel going to the injectors. I took it apart and fixed it.

I got it to start but it blew a lot of thick black smoke and when turned off seemed like it did not want to stop just slowly wound down until i forced it by covering the intake.

I pulled the 3 glow plugs. 2 where clean and the same. One was really black with build-up. I am guessing this is why it was left alone but i do not know.

So i pulled the fuel line from that injector to see what it would do. It ran with almost no smoke. I turned it off and it stopped just as i thought it should. No longer a slow stop.

This makes me believe i have a leaking injector in that cylinder. Anything else i should check? Any way to test the injector? Would you do a compression check cold to make sure it is worth the money to repair at this time? What thread and size is the glow plug? How much compression cold should i expect if you think i should test it?

Could it be something i did in the injector pump when i repaired it?

Any thought?

Jerry/MT · Apr 2, 2023

robdean said:
I have an 08 kubota D1105 Generator. I just got it and it was unknown the condition it sat for a long time since it was not needed.

It would not start so i found the injector pump was stuck and it had no fuel going to the injectors. I took it apart and fixed it.

I got it to start but it blew a lot of thick black smoke and when turned off seemed like it did not want to stop just slowly wound down until i forced it by covering the intake.

I pulled the 3 glow plugs. 2 where clean and the same. One was really black with build-up. I am guessing this is why it was left alone but i do not know.

So i pulled the fuel line from that injector to see what it would do. It ran with almost no smoke. I turned it off and it stopped just as i thought it should. No longer a slow stop.

This makes me believe i have a leaking injector in that cylinder. Anything else i should check? Any way to test the injector? Would you do a compression check cold to make sure it is worth the money to repair at this time? What thread and size is the glow plug? How much compression cold should i expect if you think i should test it?

Could it be something i did in the injector pump when i repaired it?

Any thought?

You shouldn't mess with the injection pump unless you know what you are doing. You may have messed up the delivery valve setting on that cylinder or as you surmise, the injector maybe bad. Take the suspect injector to a diesel shop and have it tested. If it tests OK, test it on the engine and see if the problem still exists.

If the problem persists, maybe one of the injector pump specialists on these forums will respond and help you check out the pump.