Mystery with a Gen-set

[Jolly Roger]

My three cylinder 120 volt diesel genset suddenly decided to only run on tick-over, and won’t give any current through the generator. It accelerates immediately it starts up, then after about ten seconds drops down to tick-over. I’ve had the injectors tested and changed the fuel filter, then bled it carefully—still it won’t accelerate to normal running. Any ideas please?

[hummingway]

When you bled the injectors were you getting enough diesel to be sure the injector pump is working properly?

[HopeFloats]

Hi Jolly Roger,
Have you checked for contaminated fuel?

[Jolly Roger]

Thanks for your interest:
First Hummingway: I don’t know how to assess the amount of fuel at the injectors to know if the pump is operating properly. I squirts out of the injector pump bleed nipple about two feet, and also runs freely out of the pump to injector connections. What other test might there be, bearing in mind I had the injectors tested and cleaned when it ran okay, before the solenoid problem?
HopeFloats: I thought about contaminated fuel, but the same line also feeds the main engine, which still runs perfectly.
What I can’t figure out is why the engine starts first crank, runs for a few seconds at proper revs, then drops to tick-over and runs as long as I leave it?

[DeepFrz]

Solenoid problem?

[Opie91]

What type of genset is it?

[Jolly Roger]

Yes, but I didn’t mention that because I can’t imagine it is related to the physical running, or rather tick-over of the engine now. The hold circuit on the solenoid kept killing the motor directly after it started. I thought it needed a new solenoid but I traced it to a bad connection with the hold wire on the solenoid plug. After I fixed it the motor ran fine, until now, when the present problem occurred.

[Jolly Roger]

Oie91:
I knew someone would ask me that. I feel a bit of a fool, but the fact is I can't remember the make and I'm not on the boat. It's something like Kabato, or similar sounding name. Three cylinders, turning a Newage 6.5 kw generator, or rather, it did.

[Opie91]

Is it a Kohler?

[Sailmonkey]

Usually the Kubota 3 cylinder genset engines are a model 905. That being said, I've seen both electric and cam actuated feed pumps on these things.

But before we go that far, when it's just ticking over, is the speed smooth like idle? or is it rough and irregular, like fuel starvation?

If rough and irregular you have a fuel delivery problem.

If smooth like idle, you have a governor issue. It could be as simple as setting the speed again and being done with it, or as complex as replacing the governor. I'd be willing to bet that the throttle adjustment screws got moved somehow though.

[Jolly Roger]

The idle is rough, so I'm prepared to buy a new fuel pump and try it. If it solves the problem great, if it's not the pump I have a spare for when it finally conks out. What sort of 12 volt pump would be best? What sort of pressure do I need.

[Sailmonkey]

I've used facet pumps before, and they're usually available at your local napa....or similar

https://www.pegasusautoracing.com/pr...asp?RecID=9736

[bobofthenorth]

If it happens that he has an Onan I think he needs more pressure than that pump will deliver - 12-15 PSI is the number that sticks in my head.

[Sailmonkey]

The listed pump is the same one that I put on the 6KW powertech generator (Kubota D905) at the house. The GPM far exceeds what the engine requires, and as near as I can tell, the pressure is sufficient to flood the plungers without starving the engine of fuel.
Your Mileage May Vary

[Jolly Roger]

The engine is a Kubota D905 with a Newage 6.5 wk generator. There are a ton of different FACET pumps available. Which one is the one for this unit? 12 volt system. I'd like to get one ordered.