esseye
[B]Model #: (00[/B]5243[B]-?) [/B][B]Serial #: ( )[/B]
[B]Propane or Natural Gas: [/B]NG
[B]Length of gas pipe feeding the generator: [/B]<15ft
[B]Size of gas pipe feeding the generator: [/B]1in?
[B]How long since the last full maintenance:[/B] 10mo
[B]How long have you experienced this problem: [/B]2mo (maybe)

[B]Description of problem:[/B]
Recently had a ~6 hour power outage from a storm while we were out of town. Noticed from alarm system/etc notifications that backup power did not cover the outage. It's unclear how long it did or if it did for any significant period. When I came back, I checked the generator and had an Overspeed LED lit. I reset the unit and let it exercise, which it did fine. I checked the diagnostics I could find for overspeed conditions and went back and replaced the air filter and cleaned everything (was already pretty clean) and checked the stepper motor operation. Everything seemed fine.

I let it exercise and it exercised fine. I let it sit for ~1 hour, and then went back out and tried to put it in manual and start it. The generator will crank and fire, but the moment it fires it immediately shuts off. It repeats this endlessly until turning manual mode off. It doesn't sound like it's running rough and it cranks and fires immediately and strong.

[B]Steps you have taken to resolve problem:[/B]
I followed as much of the troubleshooting diagnostics manual as I could describing these states - but I don't have tools to test spark/etc. I don't really suspect it's a spark issue given it fires up well and runs fine in exercise mode. Seems like an electronics/sensor issue. I tested the rpm sensor as described (which is just a continuity test, don't see a description for how to test the actual rpm sense). Not sure what to test yet, hoping there's maybe a common problem with these models that leads to this? I suspect if I engage a tech in this it will be a throw sensors & electronic parts at it until it works kind of fix. I can do that myself, but the electronic components are pretty pricey, so I'd like to avoid replacing them unnecessarily, and also welcome suggestions for retrofitting improvements rather than hard-to-find replacement bits.
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grsthegreat
not sure how old your generator is, but have you had the valves adjusted?
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esseye
grsthegreat;n60138 wrote:
not sure how old your generator is, but have you had the valves adjusted?


It's 11-12 years old now I believe. That's on my list of things to do now that I found a description for how to do it. Is it likely that valve adjustment could cause this problem though? I typically would expect valve adjustment to make it start rough, fail to start, run lumpy/etc. It doesn't seem to do any of that.
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Peddler
I assume without looking up the serial number that this is a older unit that has the LED annunciator instead of the digital display. If that is the case then you have to determine if the overspeed fault was solid or flashing. A flashing overspeed simply means there is no AC output. This is often associated with an engine that tries but fails to start or a VR problem. The first thing you need to do is get the unit so it starts well, adjust the valves, check the choke plate check the coils. If you still have a flashing overspeed then that is a different path all together.
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esseye
Peddler;n60143 wrote:
The first thing you need to do is get the unit so it starts well, adjust the valves, check the choke plate check the coils. If you still have a flashing overspeed then that is a different path all together.


Any suggestions here? The unit cranks & fires great with no hesitation. So I know it's getting fuel and the coils are working. It just immediately shuts itself down after it starts, but doesn't give me any LED indicators as to why. It seems to not do this if the unit was cold when it started, but will not run if the unit is already warm. At least that's the best correlation I can get so far. When the unit is cold and hasn't run for a day and exercises, it starts & runs flawlessly for the cycle and gives no faults.

You are correct it's an older unit with LEDs and no LCD.
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Peddler
I would check the valves for clearance of .004 and then I would make sure the throttle rod is connected to the throttle shaft and that the stepper motor is moving the throttle shaft to the wide open position. If all that is happening then I would remove the air cleaner top and observe the choke to make sure it is cycling open and closed., At the point I would stick my fingers down the ventury's while cranking for a couple seconds to do a hard choke to see if it would fire. Try all that and get back to us with the results. Good Luck.
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Peddler
I just reread you response and would say if it runs cold but not hot I would not hard choke the unit as suggested. I would lean toward either high gas pressure or bad coils. If you have a 2 psi gas system with a secondary regulator at the generator you need to check the vent on the regulator to make sure it isn't clogged and generally confirm the gas pressure at the demand regulator isn't above about 12" WC if the delivered pressure is good even after a cold run I would look to the coils firing out of time. You can try pulling one plug wire off and see if it will start the twins will run on one cylinder without problem,
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esseye
Thanks again - no regulators beyond the meter itself, just pipe from there into the unit. The choke seems to operate fine, I started it without the air cleaner as part of the process. The choke opens as it cranks and fires, but the unit fires and shuts down before the choke has to cycle at all, so can't really verify its behavior beyond that unless I can get it to remain running for longer. The stepper seems to operate smoothly and there's no resistance on it. Coil is firing down both, but I suppose it's possible the plug isn't actually igniting. I think I'd be able to notice that from listening to it run, but worth checking. I didn't notice any smell of unburnt fuel either, which I'd expect to notice if one cylinder wasn't firing.
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Peddler
These units will run full speed on one cylinder and you can't detect a miss without an IR gun. Did you check the valves? You can't tell if the coils are bad by checking for fire, the problem is a timing issue.
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