Generator

[RottwylrRVrs]

My Onan generator will not start, I have called everyone and with the backlog they are scheduling weeks out. I am 100s of miles from home so waiting around isn't possible and with the heat summer driving long distances without AC is not possible. Is it possible to carry a portable generator and drive with it connected and running?

 

[TJ&LadyDi]

Not a good idea for several reasons. First, properly venting the exhaust will be a problem. Then, there is properly securing the generator In place; that won’t be easy either. Getting it properly connected electrically would be tricky, too. And, it would take a 2KW generator to properly start and run a single AC unit.

What Onan generator do you have and what is the starting problem? Bad starter; won’t turn over? Cranks OK, but won’t start? How long since it has been serviced? Bad fuel filter?

Let us know what the problem is and maybe someone here will have some thoughts.

TJ

 

[RottwylrRVrs]

Cranks but won't turn over..... No idea why and I can't find anyone locally that will look at it. All say they are booked weeks out. Don't know last service date, I bought it early May. Venting is not an issue, I have a cargo carrier behind on the hitch and the power plug is in the rear compartment so could easily plug in. I thought of this because I saw a box truck at a dog show where they traveled with their portable generator running to cool the dogs in the truck. I know it will take a powerful generator but I don't know what option I have. ALL I need to run is the front AC between stops (where the dogs and I are, and it pulls under 20 amps when running)
It is an "Onan Quiet Diesel 7500"

TIA
Michelle Lennon

 

[KR1973]

I have an Onan 7500 diesel on my work truck. The gen wont start if its low on oil so that's the first thing I would check. If it runs out of fuel it takes a while to get fuel back through the injection pump before it will start also. How many hours in it? Was it running normally and shut down on its own? Did you shut it down and now it wont start? The starter switch on the unit should flash a code if it wont start or shuts itself down. Is it flashing a code?

 

[RottwylrRVrs]

OMG I think this worked. I did an oil/ filter change and she is RUNNING!!!!!
THANK YOU!!!
Michelle

 

["EZ"]

OMG I think this worked. I did an oil/ filter change and she is RUNNING!!!!!
THANK YOU!!!
Michelle

The generator will also stop running if your fuel tank gets below 1/4 tank. If this happens it may take several attempts to get the generator's fuel pump primed with diesel fuel again so it will start. If you have the generator running and notice you're getting low on fuel, turn the generator off until you can stop for more fuel. This way it should start right back up.

 

[RottwylrRVrs]

Yes, that I understand, and that did happen to shut it down. But even with a full tank it wouldn't restart. Changed the oil and filter and we are 4 hrs into today's 6hr drive and no issues!!!
Thank you!! $30 spent vs HUNDREDS of I JAD found an available tech!
Michelle

 

["EZ"]

Yes, that I understand, and that did happen to shut it down. But even with a full tank it wouldn't restart. Changed the oil and filter and we are 4 hrs into today's 6hr drive and no issues!!!
Thank you!! $30 spent vs HUNDREDS of I JAD found an available tech!
Michelle

If running it below a quarter of a tank is why it stopped running, that is also why it was hard to start. The oil change didn't fix it. You ran the fuel system of the generator completely dry. This is why it was hard to start. So it takes a while to get the pump primed again after you fill the main tank again. You cranked and cranked and cranked on the generator which helped to prime the pump. It just happened to start after the oil change but the oil change wasn't what fixed it. If you run it below 1/4 of a tank without turning the generator off, it will be really hard to start again.

I'm not sure about your coach but on mine if you happen to run the generator out of fuel, you can re-prime the pump by holding the rocker switch down while the light on the switch is on. Hold it for at least a minute. This will run the electric fuel pump for a while and will bring the fuel pressure up making it easier to start. If it doesn't work on the first try hold it down for another minute. Of course the main fuel tank needs to have been refilled before trying this.

 

[TJ&LadyDi]

If running it below a quarter of a tank is why it stopped running, that is also why it was hard to start. The oil change didn't fix it. You ran the fuel system of the generator completely dry. This is why it was hard to start. So it takes a while to get the pump primed again after you fill the main tank again. You cranked and cranked and cranked on the generator which helped to prime the pump. It just happened to start after the oil change but the oil change wasn't what fixed it. If you run it below 1/4 of a tank without turning the generator off, it will be really hard to start again.

I'm not sure about your coach but on mine if you happen to run the generator out of fuel, you can re-prime the pump by holding the rocker switch down while the light on the switch is on. Hold it for at least a minute. This will run the electric fuel pump for a while and will bring the fuel pressure up making it easier to start. If it doesn't work on the first try hold it down for another minute. Of course the main fuel tank needs to have been refilled before trying this.

You may be correct, @EZ, but it is also possible that a low oil level in the generator caused the initial shutdown. Either…or, conceivably, both…are plausible causes and neither should be overlooked. Checking the oil level might have helped determine whether that was the cause of the initial shutdown. Adding oil may have been as effective as changing it..

Now, it is absolutely true that running the generator out of fuel will result in the need to re-prime the fuel system before it will start again. As @EZ notes, many diesel generators have a two-position switch that allows for doing that, along with energizing the preheater.

Either way, @RottwylrRVrs was able to get the generator going and some valuable lessons were learned. That’s the real benefit of a forum like this; passing information along to others when they need it. Well done, all!

TJ

 

[Beetle77]

Great that you got it running again!. Just for interesting info about putting a generator on the back, I did that on my 98 diplomat when my Onan was down and waiting on parts. I was facing a drive to st Augustine fla in July and knew it would be a hot drive without my rooftop running, so I bought a low end 4K generator from northern tool and strapped it down to the hitch mount cargo basket and plugged it in. It worked great running my front ac unit so I hit the road feeling like a genius. Two miles down the road the generator shut down , got out to restart it and saw the low oil shutdown light was on, problem was the generator engine used an oil splash oiling method, not pressurized. Worked fine when sitting still , but bouncing around on the road caused it to shut down. Anyway , hot drive to Florida.