Onan Generator stalls after oil/filter change

[JuiceClark]

All this Onan genny talk reminded me I had a new fuel filter to install. As I snapped it in, I looked around and can't believe the thing runs at all. (but it's running sweetly)

You can see here two positive wires coming into this thing but no ground. What is that, the fuel pump? I guess it grounds itself.




And look at that wire with no place to go on the left side. It's a female blade connection and I'll be damned if I know where it's supposed to go.




There's a few fuel drips outta' this thing and it needs a lot of time. But it'll keep running until I spend a bunch of money on it. That's the way it works - they don't die until you pay for an overhaul or spend days working on it!

 

[Captain Ralph]

Glad you got it.
Every 100 hours??
Both fuel filters?
How did the Racor bowl look? Do you drain them when servicing?

 

[Captain Ralph]

All this Onan genny talk reminded me I had a new fuel filter to install. As I snapped it in, I looked around and can't believe the thing runs at all. (but it's running sweetly)

You can see here two positive wires coming into this thing but no ground. What is that, the fuel pump? I guess it grounds itself.

That is the wire connect that causes problems. I see in your picture, it already bit somebody and was fixed with new crimps.

 

[JuiceClark]

That is the wire connect that causes problems. I see in your picture, it already bit somebody and was fixed with new crimps.

Yeah, those red crimps are probably the only new material on the thing.

I wondered if the loose wire I have on the left was the one you were talking about. Seems it would have gone under that wall to the left and up into the control panel area.
I hope I didn't yank it out of somewhere when I was tinkering with the bad connections in that voltage regulator area.

 

[Pascal]

If your oil changes are very 100 hours you can do the fuel filters every other change.

The two wires with the red crimp are connections to the fuel shutdown inside the injection pump. If you look right across there is a terminal with a metal strip. That s the ground

Not sure about that loose wire, could be the connection to a gauge sender? Is there a sender above it on the coolant tank?

 

[JuiceClark]

If your oil changes are very 100 hours you can do the fuel filters every other change.

The two wires with the red crimp are connections to the fuel shutdown inside the injection pump. If you look right across there is a terminal with a metal strip. That s the ground

Not sure about that loose wire, could be the connection to a gauge sender? Is there a sender above it on the coolant tank?

Dunno. My only gauge is oil pressure and it's working.
I looked and felt around everywhere - except over behind the control panel. Can't find a blade anywhere. One day, I'll find where it goes, plug it in and then the genny won't start.

 

[dawg6]

How did the Racor bowl look? Do you drain them when servicing?

Bowls looked clean, so I didn't drain them. I guess that's another thing to add to my list next time!

 

[Captain Ralph]

Dunno. My only gauge is oil pressure and it's working.
I looked and felt around everywhere - except over behind the control panel. Can't find a blade anywhere. One day, I'll find where it goes, plug it in and then the genny won't start.

If you have the original print set schematics, there are numbers on the original OhNo wires. That will tell you what/to/from.
I'll bet to the run injector. Been some years now but I only remember one wire going to it.

 

[Avenger]

Been some years now but I only remember one wire going to it.

If I was the gambling type I'd bet that's where they got the power for the electric fuel pump.

 

[Wow57pro]

The wire on the left goes to a temperature sensor mounted on the exhaust riser. It should ground and shut the engine down if there is no water flow out the exhaust.

 

[JuiceClark]

The wire on the left goes to a temperature sensor mounted on the exhaust riser. It should ground and shut the engine down if there is no water flow out the exhaust.

Thanks! I saw an old picture or two of this genny and a single wire headed back to that riser. So, I scoured that area, over and over, looking for it and there isn't a plug for it. All the hoses have been replaced over the years and that riser doesn't look more than a decade old. They must've replaced it without the sensor....and shut the need for it off somehow.

 

[jamesaelliott]

Check the heat exchanger for leaks

 

[ageless]

I thought I would build on this thread in that I am experiencing several of the well known Oh No issues starting with not wanting to remain running after main filter change. I discovered a fuel leak at the pump so it's time to go electric. I have a 20kw MDL4

Dilemma: 1. manual says 12v system, nope! 36v at the starter.
2. manual shows gph at half/full load but I see no pressure specs

anyone who has used a 24v pump on an MDL4 care to share the specs on the pump you converted to? Anyone who might know the pressure specs?

I also have a leak from a screw or adjustment above the injector lines on the injection pump housing, I was going to remove it and attempt to find a replacement o-ring. One member mentioned doing this in another thread, hopefully he'll chime in.