Generator Stalls out

[txnese]

I'm having a weird problem with ONAN Micro Quiet 4000. Sitting in my driveway, the generator stays running with no issues. While I'm driving, the generators stalls out after about 20 minutes and won't start back up. It will start up again after sitting for few hours. Fuel tank is full. I'll be testing different scenarios next couple of days.

[txnese]

Here's the final result. After changing the filter and pump and messing around to get it started. I let it run for 2 hours in the driveway, took it on a 3 hour drive to camp and a 3 hour drive back. No issues. Thank you all for your input.

[Mich_F]

txnese wrote:
So the generator died, I took off the fuel line, pushed the primer, and no fuel and no sound from pump. I decided to replace the fuel pump and filter. I pushed the primer to confirm pump is running and look for leaks, good there. Now when I try to start the generator , it sounds like it’s hydro locked. Or won’t crank and got 3 flashing lights. Blown generator starter fuse? Did I prime too long?

About 30 minutes later. I decided to take out the spark plug, no fuel on the plug. I put it back in and the starter worked and generator cranks up and now i'm just waiting to see if it dies. Running out of time today, so will update after next big trip.

I believe the 3 flashes is telling you it has stored a fault code. If you press the stop button three times within 5 seconds. it will again flash three times. Press the stop button one more time and it will flash the fault code. It will be a single flash or more followed a few seconds later by more flashes. It will repeat this code. There could be more than one fault code and it will flash any additional code the same way.

[txnese]

So the generator died, I took off the fuel line, pushed the primer, and no fuel and no sound from pump. I decided to replace the fuel pump and filter. I pushed the primer to confirm pump is running and look for leaks, good there. Now when I try to start the generator , it sounds like it’s hydro locked. Or won’t crank and got 3 flashing lights. Blown generator starter fuse? Did I prime too long?

About 30 minutes later. I decided to take out the spark plug, no fuel on the plug. I put it back in and the starter worked and generator cranks up and now i'm just waiting to see if it dies. Running out of time today, so will update after next big trip.

[D_E_Bishop]

Kind of a funky way of checking the pump but effective. I was having a different problem with my 5.5 Onan from 2001, I pulled the hose off the engine and put in a "T" with a small petcock on the stem side of the "T". The top was reconnected to the engine.

When the generator engine died, I opened the petcock and tried to start the engine, darn near filled a one cup bottle in just a few seconds but would not restart. Found the problem later and still waiting for parts from Onan.

[klutchdust]

whizbang wrote:
I had the exact same problem. Replacing the pump and filter assembly fixed it.

I've experienced issues with engines dying and just the fuel filter was the culprit. Van type box trucks with inline filters mounted in the frames about midway from the fuel tank. I wonder if the fuel filter for the generator could be the issue here and not the pump also. Same symptoms as described.
Good post and suggestions.

[whizbang]

I had the exact same problem. Replacing the pump and filter assembly fixed it.

[txnese]

Wasn't the oil level. It died twice on me this weekend. I'll be testing a few things out over the next couple of days, now that I'm home with all my tools.

[txnese]

After topping off the oil and driving home 2 hours, so far so good. I'll check the rubber hoses when I get a chance. thanks everyone.

[PSW]

I had a similar problem once on the engine of the motorhome. Dry rot on a rubber part of the fuel line. Driving, the temps apparently increased and it opened up a bit and starting shutting down. Looking at your location and assuming that is Pearland, TX, that makes sense because it can get pretty hot early in that part of TX. And, since your rig is now fifteen years old, I would sure suspect that as a possible culprit.

[txnese]

There's only 20K miles on this 2003 and everything looks original. Wouldn't doubt it if I had some dry rotted lines. For now, the oil was near the bottom of range, so I topped it off. We'll be parked for the next of couple of days. Will keep y'all posted. thanks for the input.

[russelln]

Had a similar problem. Tried a new pump and filter, still would stop sometimes. Eventually found a crack in the rubber section of fuel line on top of the gas tank. Could just see it looking through the gap with a flash light. Had to drop the tank down and replace it.

[Bear_N_Honeys]

I will have to try both of your suggestions. I have the same issue.

[naturist]

Low oil? They all have a low oil shut-off, and if you are right on the edge, it would run fine sitting in the driveway, but hit a bump on the road, and the low-oil shut-off could be triggered.

[BruceMc]

How old is the unit? Most of the time, this behavior points to the Onan fuel pump. They'll run for 10-20 minutes, then die.
Odd yours stays running while parked, but fails while underway. It could be heat or vibration that causes the pump to quit.

Next time it dies, park, kill other sources of noise like your engine, then try to prime it. After a few seconds on prime, the pump should start making noise. If it's silent, then it's most likely the pump.

Let us know what you find.