002a Runs Great then Dies

So, I Haven't run my genset for awhile. Maybe 3 months. I have it setup to a be whole house gen (less high amp stuff). So I figured I would fire it up, switch over and let it run a bit. I checked things over, oil good, fuel good (not more than 4 months old), cap set to "open" (was in closed, new). I warmed it up, primed and started like a champ. I let it warm up for about 5 min, since it was about 87F outside.
I killed my house breakers and brought the Gen live to the panel. I brought all up less high amp stuff (hot water heater, oven, clothes dryer). I jacked the AC temp up so it wouldn't come on right away. All good, less than 20% load. Then I added on the AC. It blew some smoke, but settled at 75% load, Hz good. Hovered about 59.8 Hz.

So I went about my ToDo's. About 10-15 min later, it just stopped. So I killed everything, bringing everything back to the way it was on utility. Looked everything over, and no clue. I tried to start. It sounded like it wanted to, but it would not.

A day later, I checked it over. Still no clue, but it started right up. Puzzled, I turned it off since it was about to rain pretty heavy again.

So I'm looking for suggestions to why it would have died? Think it was a load issue since I was already at 75% or something else? But load doesn't make sense if it didn't start with no load.

Could be a number of different things. Could have been load and the shut off solenoid hit the injector pump lever and jammed it just a little. I think the only way you will be able to find out is test again, while your standing next to the unit. If it's load then you'll know and if it shuts down again with no start, make sure the fuel cutoff solenoid retracted and the linkage came up completely.

Sounds good. I might stick a gopro camera in front of it just to record what happens just in case I step away. Does it shutting down in this manner damage the gen head when it shuts down engaged? I know it is a major no-no to start with the main breaker on, with load applied.

It's not good for the voltage regulator for sure but the head will be fine.

I installed the aftermarket on that is mentioned on this site. I think it was built to handle a bit more abuse. Hoping anyway.

You'll be fine then, Triple Jim stands behind his product and has done extensive testing on it.

Have you checked fuel filters and fuel pump, including pump screen/filter?

jamboly said:

Have you checked fuel filters and fuel pump, including pump screen/filter?

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So, in short no. When I run the prime I hear it pumping just fine back into the tank. If it were a filter issue, I would think the fuel circulation would be reduced. Also, after it cooled down, it ran fine for about 10 min. So if it were a filter issue, I would think it wouldn't run well at all after it cooled down.

jamawieb said:

Could be a number of different things. Could have been load and the shut off solenoid hit the injector pump lever and jammed it just a little. I think the only way you will be able to find out is test again, while your standing next to the unit. If it's load then you'll know and if it shuts down again with no start, make sure the fuel cutoff solenoid retracted and the linkage came up completely.

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Heh, gotta pull out the TM to find out where the "fuel cutoff solenoid" is located.

Right above the injector pump. It's the rod that comes down with the rubber boot on it.

Are your shutter louvers opening after it warms up with a good load on it? You said it was 87 F outside and was running at 75% load when it died. At that temperature and load I would expect that the shutters would open up quite a bit...at least ~75% open. If there were any significant cooling restrictions (stuck shutters, mouse nests, dirt daubers, etc) it could trip the overtemp cutout switch. After it cools it would then run fine until it overheated again. IIRC, there is a test procedure for testing the switch in the TM.

I had a similar issue about 2 years ago. turned out my filters on the pumps had been getting dirty. after cleaning them the machine started up and ran like a champ, didn't shut down on its own. Ran it for an hour and had no further problem with that.
metalworker393

So, I did another test. This time, I ran it with no load for an hour. Ran great. Then, ran it at 25% load for 30 min, just fine. Then I took it to 75% load for 5 min or so, ran fine. Then, took it to 95%. This is the heaviest load I've had on it. It handled it fine. For 6 min and 13 seconds. I had a gopro on it when it died. Now, like a dummy, I didn't try to restart. But the throttle linkage seemed free (up near where the fuel shutoff solenoid is). Watching the video, there is no load spike, just Hz dropping. It sounds like it was "turned off".

See Video: https://drive.google.com/file/d/1G6btJ4RIkay4k1etL8pkkSLxBBy_d89z/view?usp=sharing

100% that is the fuel solenoid shutting it down. That is either the oil pressure switch or temperature switch.

So, glad you asked. (haha) My oil pressure switch is bypassed. I installed a new one, but I haven't hooked it up (ie: someone, at some point, just bolted the two leads together). So would this leave temp? I didn't even know this had a temp switch. Time to search the TM's again. Thanks for the help. And as always, if I need a good slap, please. Proceed.

Hmm...Page 3-2, Figure 3-1, item 11: High Temperature Switch

I don't have the ASK installed, as I'm overhauling it with modern sound suppression materials, but I can't imagine it's really getting overheated. Since this was air cooled, I never really gave it any consideration of overheating. That being said, I guess the temp switch could be bad. Hopefully it's not anything too special.

Are the louvers under the exhaust pipe opening. I would say that the switch is working but the louvers are not opening since it starts and runs fine. You could open the lovers by hand and pry a small piece of wood in between the louvers to keep them open to see if it runs properly.

jamawieb said:

Are the louvers under the exhaust pipe opening. I would say that the switch is working but the louvers are not opening since it starts and runs fine. You could open the lovers by hand and pry a small piece of wood in between the louvers to keep them open to see if it runs properly.

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Yeah, they are closed before starting. Open up as it gets warmer, close again as it cools off.

n5yzv said:

Yeah, they are closed before starting. Open up as it gets warmer, close again as it cools off.

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If the low oil pressure switch is bypassed and its only shutting down under sustained high load & restarts when cooled off, it sure seems to point towards the High Temp switch being activated. Even if the shutters are opening properly you still need to check for any restrictions behind the "Close to run" cover that latches closed just above the oil dipstick. Look into the cooling fins to insure they are open to full air circulation pass through. If you need to replace the high temp switch they are fairly common and available. For reference try a search for: "Switch, Thermostatic P/N: 0309-0277 MFG: Onan/Airpax"

You do have the cover closed and latched? If the cover isn't securely closed, the genset will overheat because of airflow issues.