Onan Generator, quits after start.. Update

Probably needs a new carb, they are about $250 on amazon, the gas with ethanol really screw these carbs up, I now put stabil in every tank.

IF your fuel tank is a quarter down the gen set won,t run.

midnightsadie wrote:
IF your fuel tank is a quarter down the gen set won,t run.

Don't you mean if you have less than a quarter tank of fuel the gen won't run? :)

I had this happen on my 5k Onan. The first thing the generator does when it starts is look for 110v power. If no 11ov found it shuts down. I believe Cummins installed new brushes and cleaned the stator, but it's been a while (2 MH's back) so the stator part might not apply. The genny didn't throw an error code, so it took a diagnostic approach to find it.

Your situation may be different, just sharing my issue.

You will probably need to visit an authorized service shop Onan/Cummings

The fuel pump is probably driven by a relay.....but if the pump was going off with the switch, I would think it would run for 30 seconds or so before dying.

I suspect that the "empty tank" safety would operate through that relay too......so it almost sounds like the ignition is being cut off when the start switch is released.

Given the symptoms, it is definitely NOT a carb problem.

Because oil is full does not mean the low oil pressure switch is engaging to allow the unit to run

I found my link to the troubleshootiing guide

http://www.flightsystems.com/pdf/onan-rv-troubleshooing-guide.pdf

chucl66 wrote:
This is a follow up question.
5BGE gas powered (2000 Damon Intruder. Have replaced fuel pump and filter, but still shuts off when switch is released. Oil level is full, battery is fully charged. Full tank fresh fuel. It runs until the switch is released
What suggestions do you have to trouble-shoot for additional solutions to the problem?
Thanks for any help.
Chuck

Chuck,
Wow, does this bring back some OLD, ANCIENT MEMORIES! Let me ask you something here. When you say it runs until the "switch is released",:
1. Are you talking about the start switch/toggle?
2. If so, how long will it run, if you hold on that switch?
3. If it continues to run, as long as you're holding on the switch, I really can't see that it's fuel related but, I'm no expert.
4. If you were to start it, and hold that switch in the start position, (again, assuming it's the START toggle,) and it keeps running, until you let off the switch, I'm going to assume that, for some odd reason, you may be shutting of the spark when letting go of that switch.

I say it brings back ancient memories because, way back a few hundred years ago, GM, Ford and pretty sure Chrysler all had what was called POINTS ignition. (I think some of you "old timers" remember those don't you?). Well, long story short, in most of those POINTS AND CONDENSER operated ignition systems, when you hit the start switch or, turned the key to the start position, you energized the points with a full 12V from the vehicles electrical system.

But, engineers determined that most points, could not operate on the full 12v for very long because it was too much voltage for them so, there was actually 2 systems that fed power to the points. The first was the full 12V that was energized when in the cranking/starting mode. Once the engine caught and was running, you let off the start switch and, that sprung the key back to the "run" position.

In that position, another power system took over the responsibility to feed the coil and the points. But, that system was routed through what's called a "Ballast Resistor". What that resistor did was, step down the voltage to the points to about 8V or so. That kind of lower voltage was more easy on the points and, made them last longer. But, what would happen once in a while, actually more often than most folks knew, was the Ballast resistor would burn out.

When that happened, you would find the EXACT SAME SCENARIO that you're encountering now. The engine would start and run, as long as you kept the key or, start button, in the start position. But, if you let off, the engine would quit. Talk about a bunch of frustration.

Now, I explained all this because, I don't have a clue if your gas generator has anything like that kind of old style starting/running system.

If you keep starting it, and it runs, while holding down the start switch, I'd say you've got enough fuel in the tank. And, I don't know how much fuel that little carb holds but, even if the fuel pump was being shut down due to you letting off the start button/toggle/switch, you should have enough fuel in the carb, to keep it running at least for a short time, maybe a minute or so, or more.

But, it shutting down the micro-second you let off the switch, is what's got me puzzled. Good luck and, please post what you find out is the issue.
Scott

You are liable to find that the genset is not producing power. Most of them won't run if they are not producing electricity. May not be anything wrong with the motor itself. There are a few things that cause them not to produce electricity (voltage regulator, brushes, stator).

mine 2007 5500 had same type of problem would run as long as you held start switch on when letting off switch would die found brushes bad one brush looked like new other brush wore out got new brushes and cleaned armature 3 years later same thing don't know why probably bad armature I just keep replacing brushes every 3 years and all is well

chucl66 wrote:
This is a follow up question.
5BGE gas powered (2000 Damon Intruder. Have replaced fuel pump and filter, but still shuts off when switch is released. Oil level is full, battery is fully charged. Full tank fresh fuel. It runs until the switch is released
What suggestions do you have to trouble-shoot for additional solutions to the problem?
Thanks for any help.
Chuck

Just for drill, pull the fuel hose off and use a length for dipping it in a jug of gasoline. If it runs then, you have fuel delivery problems, that are usually caused by the sucking of air. The cure can be as simple as running a new fuel hose back to the tank and if you're lucky.
Having said all this, it doesn't sound like your problem, but you or anyone else, can take it for what it's worth in the future.