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Mbranch12
04-14-2014, 01:57 AM
Hi, I just bought a 2014 citation sr with the onan cummins 3200 qd gen. I understand that the gen will shut down when chassis fuel level gets down around a quarter of a tank. I ask dealer how it done this and he said the gen uses a pickup in the tank that is placed up higher and will shut down when it can no longer get the fuel. I expressed concern to this as when other diesels I have been familiar with ran out of fuel, it was a major deal of bleeding, priming etc to get it started. I called thor and they agreed with me and that this gen used some type of float switch to electrically shut the gen down, as to mimick the normal shutdown, when fuel level reached a certain point. I have had it shut down twice now at around a quarter tank and both times it took several attempts to restart(after refueling) it would surge, fluctuate, white smoke etc. just like it had sucked air. It would finally catchup and run flawless for hours. I have heard that the gasoline gens are plumbed like this, which would make sense and not such a big deal when they shutdown from low fuel. Is this normal for the diesel gens to be plumbed like this or has mine been built wrong? Thanx ahead for any suggestions Mb

chromisdesigns
04-14-2014, 02:03 AM
Hi, I just bought a 2014 citation sr with the onan cummins 3200 qd gen. I understand that the gen will shut down when chassis fuel level gets down around a quarter of a tank. I ask dealer how it done this and he said the gen uses a pickup in the tank that is placed up higher and will shut down when it can no longer get the fuel. I expressed concern to this as when other diesels I have been familiar with ran out of fuel, it was a major deal of bleeding, priming etc to get it started. I called thor and they agreed with me and that this gen used some type of float switch to electrically shut the gen down, as to mimick the normal shutdown, when fuel level reached a certain point. I have had it shut down twice now at around a quarter tank and both times it took several attempts to restart(after refueling) it would surge, fluctuate, white smoke etc. just like it had sucked air. It would finally catchup and run flawless for hours. I have heard that the gasoline gens are plumbed like this, which would make sense and not such a big deal when they shutdown from low fuel. Is this normal for the diesel gens to be plumbed like this or has mine been built wrong? Thanx ahead for any suggestions Mb

The factory guy was blowing smoke, I highly doubt they (Thor) modified the sprinter fuel tank with a float switch! Virtually every diesel engine these days has a self-bleeding fuel system, so the normal way to plumb a diesel generator is indeed straight to a pickup. There MAY be a sensor in the fuel line to detect air and shut it down, but you would need to check the generator manufacturer, I think it's unlikely. What you experience running it out of fuel is normal, I believe.

I, too, remember the bad old days when sucking air with your boat diesel meant getting out the wrenches, but it's not that way anymore.

Mbranch12
04-14-2014, 02:29 AM
Oh ok, makes more sense now. Thanx for the info.

icarus
04-14-2014, 02:30 AM
That said, the simple solution is not to run the fuel down low enough to force a shut down. In the grand scheme of things, it isn't a good idea to do so on any regular basis. All diesel injector pumps (that I know of) get thier lubrication from the fuel, starve the pumps and you starve the lube.

Icarus

Mbranch12
04-14-2014, 02:42 AM
That said, the simple solution is not to run the fuel down low enough to force a shut down. In the grand scheme of things, it isn't a good idea to do so on any regular basis. All diesel injector pumps (that I know of) get thier lubrication from the fuel, starve the pumps and you starve the lube.



Icarus


Yes, I totally agree...

dirtyguy
09-09-2014, 09:40 PM
A work around I have been doing on my 24SA is to keep the main engine running when the tank is less than half full. If I keep the main engine running, the rear Onan Diesel will run without getting shut off even when the fuel is quite low.