Onan 13.5 starts well but after few minutes, die

It starts again, it’s not fuel problem, but after few minutes, die again

If it starts, runs for a few minutes, then it is probably a fuel problem. The only other thing I can think of is the temp or oil pressure sensor is tripping out, and maybe it is bad.

David

I don't think the temp would trigger a shut down this quickly. If you leave the "Preheat" switch on (just hit it on right before you think it is going to shut down) does it still shut down. If yes then I think this eliminates a problem with a temp or oil pressure sender issue(This I believe will bypass those).

What are all the loads on it ? Have you tried starting it with no loads? Have you changed the fuel filters lately?

Could be overheating - clogged water filter, bad impeller, etc. Check temperature guage when it stops.

On the side of the injection pump is a bleed valve with a thumb wheel. Open it up a turn and try a run. If air is the problem, it will purge it. Some have it, some do not.

Can also be a failed elec lift pump. Those do crap out occasionally.

What is the exact model?

Is there any instability that you can hear or feel or see in theboutlut, or just a sudden shutdown?

What type(s) of load(s) have been present when the problem was exhibited?

Normally instability before shutdown points to fuel. Hard shutdown pointa to a safety sensor (water temp, exhaust temp, oil pressure, output voltage, etc), which could be a sensor, something in the circuit, or a real performance problem, e.g. clogged intake or cooler or bad impeller or overload, etc

DavidM said:

If it starts, runs for a few minutes, then it is probably a fuel problem. The only other thing I can think of is the temp or oil pressure sensor is tripping out, and maybe it is bad.

David

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I know that diesel motor just stop if miss fuel, but the new ones, with a lot of sensors, stop if one of them have problem

gkesden said:

What is the exact model?

Is there any instability that you can hear or feel or see in theboutlut, or just a sudden shutdown?

What type(s) of load(s) have been present when the problem was exhibited?

Normally instability before shutdown points to fuel. Hard shutdown pointa to a safety sensor (water temp, exhaust temp, oil pressure, output voltage, etc), which could be a sensor, something in the circuit, or a real performance problem, e.g. clogged intake or cooler or bad impeller or overload, etc

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I think must be one sensor, but how to test each one?

Alemao said:

I know that diesel motor just stop if miss fuel, but the new ones, with a lot of sensors, stop if one of them have problem

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With the exact model, we can look for a schematic and advise about what sensors, i.e. safety switches, it has and how to find which one may be triggering the event.


Otherwise, all we can say is verify fuel valves, check for and correct any leaks, change filters, bleed well, and see if it goes away. If you can't bleed because fuel won't come out fast, verify fuel path and the replace the lifter or push through it by adding an electric online.

You can also try jumpers across eqch of the safety switches to see if they are bad....but manually watch the associated conditions, e.g. temp, oil pressure, etc, with gauges and/or a temp gun, etc.

Also keep an eye on output voltage and frequency.

Alemao said:

I think must be one sensor, but how to test each one?

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On most systems, you can pull the two wires off each safety switch and short/jumper across them, taking the safety switch out of the circuit. Of course, you'll want to monitor the condition when you do that -- it could really be overheating or losing oil pressure, etc!

Safety switches used for shutdown are commonly daisy chained and have two wires going to each, one in and one out to the next.

The senders used to drive the gauges aren't daisy chained and usually only have one wire going in and ground to the block, or have one hit and one ground for a loop -- but not daisy chain.

You are looking for the daisy chained safety switches.

Again...knowing the exact model would be helpful. Newer units don't daisy chain safety switches so that they can report specific error codes rather than just shutting down without giving information about why,, for example.

Another (albeit remote) possibility is something in the fuel tank getting drawn onto/into the pickup tube. After engine dies, vacuum released, junk falls off/out. Rinse & repeat. Internal delamination of a fuel line hose might also be causative.

Have you checked the V-belt? If it fails, this is the exact symptom because the engine overheats pretty quickly with both water pumps not turning.

Mine was doing the same (on a Westerbeke). It was the water temp sensor, went bad. Easy fix... If it were me, I would buy all the sensors the gen has. Replace which one is bad. Then you have spares for the others and order another of the one that was bad...

Mischief Managed said:

Have you checked the V-belt? If it fails, this is the exact symptom because the engine overheats pretty quickly with both water pumps not turning.

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I’ll check today, thanks

Scottwb96 said:

Mine was doing the same (on a Westerbeke). It was the water temp sensor, went bad. Easy fix... If it were me, I would buy all the sensors the gen has. Replace which one is bad. Then you have spares for the others and order another of the one that was bad...

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I’ll order the sensors, thank you