Nanni Kubota stalling at slightest heel

[billgewater]

The fact that the engine won't even start up when heeled leads me to believe that the problem is not fuel at all. It would seem that all the injectors just are not injecting at all. Some engines do have shut down systems built in such as oil pressure etc. If it was air in the fuel or blockages then the engine should still fire up and after a while, stop.
Unless an air bubble settles inside the injector pump - unlikely though.

My own ancient Ford 590 E series engine has a small button where the throttle is attached to the injection pump. If that button is touched then the fuel is simply not injected and the engine just won't fire.

I would be looking at similar safety cut off devices around the injector pump.

Check the engine manual for safety cut off devices and go from there.

At an acquaintances farm his large stationary diesel gen set failed and it just would not start. Turned out the in line injector pump had no sump oil in it - as required - so it simply was not pumping fuel at all. Oil added, problem fixed.

Could be a similar case.

[Jack C]

Based on 2 facts presented. No firing at all on heel and previous diesel bug problems, I think it is fuel starvation at the injector pump due to a blockage that increases with heel.
The blockage moves when heeled. Think about a U tube with some mobile gunk at the bottom that does not fill the bottom of the tube. When heeled or can move and block the tube.
Try an injection pump flush. If that does not work then a pump service.

[Ninedotsix]

I'll see you one, and raise you one:

If fuel pick up is located off center (in flat tank, as in mine), the pick up is sensitive to fuel level and angle of heel.

ALSO, after cleaning tank, and a number of other operations to improve the air entrainment problem, I discovered a screen in my pick-up tube, like up inside the tube, hard to see.

Well, that's presumably a good thing to protect equipment, but with a return line to the top of tank from the injectors, it occurred to me that the injection pump could suck air back through the return line from the head space in the tank, and that this would be worse when the screen clogged.

Now, for background, I had already religiously converted to highway low sulphur diesel fuel, to ensure I had cleaner fuel (less stinky since low sulphur does not support bugs and has additives to ensure the bugs don't grow and the pump/injectors are protected); the rural tanks along shore in Chesapeake usually have dark fuel.
I had the the system was as clean as one could hope, and I keep a clean low-micron engine filter, and a 5 micron Racor 500 pre-filter, which can run years between changes on this small 15hp engine.

Removing the pickup tube strainer meant that the bypass suction would be eliminated, thus eliminating air entrainment, so remove the strainer is what I did.

As long as I don't use more than 1/2 tank (5 gallons, or a day of motoring) before adding fuel, it's AOK, with the pickup tube immersed when on stbd rail.

Racor bowl always shows clear fuel, no water or solids, and engine runs on a heel.

Fingers crossed, all better.

I'm only a little leery, since I may have introduced sulfite-reducing bacteria last year taking on dark fuel on a fuel dock. But haven't noticed a stink, so maybe no bugs, or the additives in the highway fuel have killed them.

Yes, by all means, add to the knowledge base when you find your fix let us know. (Didn't know the Nanni is built on Kubota block, a new one on me)

Cheers,
9.6

[Asmodeane]

Whoa, thank you everyone, didn't expect so many answers! This is like a treasure trove of various avenues to explore! I'll be sure post an answer to my engine woes as soon as I have any, but first I think I'll remove the tank to clean it properly, and replace the hoses. Then a thorough flush of the fuel system, and another change of the filters... I think I'll get my injectors serviced as well, can't hurt, rite?

[malbert73]

Originally Posted by Asmodeane

Whoa, thank you everyone, didn't expect so many answers! This is like a treasure trove of various avenues to explore! I'll be sure post an answer to my engine woes as soon as I have any, but first I think I'll remove the tank to clean it properly, and replace the hoses. Then a thorough flush of the fuel system, and another change of the filters... I think I'll get my injectors serviced as well, can't hurt, rite?

How about put some more fuel in your tank first hand see if the problem goes away?