Kubota D1105 Engine - Slow RPM Response to Throttle

[Godhungry777]

Does anyone have any thoughts on why this D1105 takes so long to respond to throttle movement? Where should I start looking?
See start and end of this video (start 0:53 - end 1:46)
The rail on the injector pump moves freely, as does the governor fork.

 

[5030]

When was the last time you renewed the filters?

 

[loggin]

Have you checked lift pump pressure? Have there been any repairs done prior to this happening?

 

[TractorTech]

I'm wondering if the hydraulics might be the problem. As in there is a valve that is not responding very fast. Maybe a priority valve?

 

[Godhungry777]

I'm wondering if the hydraulics might be the problem. As in there is a valve that is not responding very fast. Maybe a priority valve?

I can understand that being an issue with the bogging but would it effect the rpm response to the throttle when no hydraulics are engaged? Or is there a part of the hydraulic circuit that is active when nothing is engaged?

 

[Godhungry777]

Have you checked lift pump pressure? Have there been any repairs done prior to this happening?

Likely. I got it in this condition.

 

[Godhungry777]

When was the last time you renewed the filters?

The whole fuel system has been gone through.
Here's what I've done so far:

• emptied and cleaned fuel tank (had water, rust and gunk)
• replaced fuel filters (clogged with water and gunk from tank)
• replaced fuel lines (lines were brittle) - had injector pump and injectors tested - tested ok
• bled injector lines
• replaced engine oil and oil filter
• replaced thermostat and coolant (thermostat was stuck open)
• air filter had already been replaced - exhaust is clear
• checked governor spring, forks and flyweight. Warn but nothing broken or missing

 

[TractorTech]

Not sure about that model, but there may possibly a stepping motor on the throttle linkage. Just a thought

 

[Godhungry777]

I can understand that being an issue with the bogging but would it effect the rpm response to the throttle when no hydraulics are engaged? Or is there a part of the hydraulic circuit that is active when nothing is engaged?

I drained the hydraulic tank and removed the filters. Both were dirty. The return filter had actually pulled apart from the pressure of not being able to travel through the filter.
Filters have been ordered. I'll update when i have them in.
There was some gunk at the bottom of the tank and the oil does go creamy when the pump is running. I'm guessing this means there's some water in the system. It goes translucent again once it has settled for a while.
What's the best way to flush the whole hydraulic system so I can give it a good fresh start?

 

[TractorTech]

Drain as much as possible. You have drained the tank, now the only thing you can do is drain the oil out of the cylinders that you can.