Injectors on a Kubota 3 cylinder engine.

[Burnerman]

Hi Richard
The older mechanical injection pumps had both an electrical solenoid and a hand stopping lever - often marked stop with an arrow, curiously enough!
If the engine was stopped with this lever, it had to pushed back to allow restarting.
So, you are getting diesel now, but the spray pattern is poor......what you say about red diesel is correct - the bio content is creating blockages in some installations but usually filter changes sorts it for a while. It's particularly prevalent where farmers buy their diesel in quantity in the summer and it lies in tanks for a good while before use. I have no experience of injection pumps blocking with it though. - which isnt to say it doesn't happen!
I'd love to hear the outcome of this!
Myself, I'm a retired teacher who is a member of the mechanical engineers institute.....I fill up my time repairing grass machinery now and generally messing about with mechanical things. I've restored a couple of properties but I'm past that now!
Regards
John

 

[Burnerman]

Just scratching what's left of the brain cell fellas but have you checked the banjo connection into the injection pump, on the main fuel line?
I can't think of anywhere else it could block, but another theory is, if the injection pump low pressure side is working, fuel should be continually returning to the tank when the engine is cranking?
I mean, the darn thing was fine when you put it away at the end of the season so there can't be too much the matter with it!
John

 

[montyhound]

Thanks again for your valuable input John.

Going back to my comment about not much fuel being spilled from the pipes when I disconnected these from the injectors before taking them to be tested and my impression that they were empty even though I had been cranking the engine over earlier whilst it coughed and spluttered but wouldn't fire.

Even if I have a leak somewhere in the injector pump which is allowing fuel to flow back down the pipes from the injectors and which may mean that the pump isn't producing the circa 2000 PSI needed for proper running, I wouldn't have thought that this reverse fuel flow was possible unless air could get into the system to replace said fuel. Does this make any sense to you?

Regards

Richard

 

[Burnerman]

There's two points of thought here, Richard.....
There will be rubber pipes attached to each injector - these are called leak off pipes and they return any non injected fuel back to the tank......this doesn't indicate a fault if there is fuel visible here.
On the injection pump itself I would expect to see one low pressure fuel inlet, the three high pressure outlets to the injectors and another pipe that returns fuel to the tank if it doesn't make it to the high pressure side of the injection pump.
It does sound like the inlet to the pump is restricted somewhere!
John

 

[scooby1]

Out of interest John, whereabouts in the UK are you and what do you do to earn a crust?

Richard

John's location is in his signature pane Richard.Try and keep up, there's a good boy.

Thanks for coming back to us John. I am enjoying this. David.

 

[montyhound]

Hello again John.

You are entirely correct. I noted that fuel was being squirted out of one of the end leak off pipe banjo fittings when the fuel lift pump was operating and I had the injectors out yesterday and I assume that this connects into that part of the injector pump which returns excess fuel to the tank since there is a rubber pipe running from said end banjo to the injector pump and another rubber pipe running from the other end banjo and which must then return excess fuel from the 3 injectors and the injector pump to the fuel tank.

I got my injectors back earlier having been tested and re-calibrated and the guys said that there hadn't been much wrong with them so I'm hoping that the fuel restriction that you refer to is a partial blockage in the first in-line fuel filter which sits between the fuel tank and the lifter pump. In any event, I'll replace both in line fuel filters tomorrow when I will drain the tank and replace it with a few litres of fresh white diesel and then try starting the recalcitrant beast having re-fitted the injectors.

Thanks again for your kind advice and interest.

Richard

 

[Burnerman]

Fingers crossed!
John