Generator stops running

[robert64]

used the generator quite a bit the last few weeks while on vacation. when we returned try to start it several times starts up runs about 10 seconds and shuts down, checked the oil and anti freeze both full. wahat next? bob!

 

[Stevecmaynard]

Maybe check the impeller or strainer. If there is no seawater pickup the gen will shut down at some point for temp protection. I am not sure how long this will take. Also if it is not picking up water the gen should be louder than normal when it starts up.

 

[matthewmiller01]

Check the batteries. This happened on my test drive before I purchased. The dealer changed the weak battery/batteries and that fixed it.

 

[dwna1a]

Same thing happened to us, it turned out to be trash in the carb. By using it so much we stirred up the fuel and the trash in it.

 

[JimFromMD]

Same thing happened to us, it turned out to be trash in the carb. By using it so much we stirred up the fuel and the trash in it.

--Edit-- Just saw you were diesel, so may not apply --

Try cleaning the carb with some carb cleaner. Also there's a generator fuel filter on the generator itself, and some installations have a spin on filter in the line between the tank and the generator's fuel filter too similar to what is on the main engines.

There's a also a long generator thread on the "general discussions" forum.

 

[jerryd5515]

used the generator quite a bit the last few weeks while on vacation. when we returned try to start it several times starts up runs about 10 seconds and shuts down, checked the oil and anti freeze both full. wahat next? bob!

I have an Onan 13.5KW gen and mine stopped after 8-10 secs. The amber light on the "Start/Preheat-Stop/Prime" switch would flash 7 times and that indicated a "Loss of raw water flow" and one of the corrective actions was to replace the impeller. When I closed the gen seacock and removed the impeller cover, the impeller was missing most of the vanes. The gen had worked fine the previous time it was used. I replaced the impeller and lubed it with soapy water, reinstalled the impeller cover and o-ring and then tried to open the cover to the heat exchanger to collect all the vane fragments. The oil filter is partially blocking access to the heat exchanger cover, but the cover can be removed with a long socket wrench extension. All the impeller vane fragments that had collected in heat exchanger were removed, cover reinstalled and I was good to go.

 

[Art]

Definetly sounds like an overheating problem. Check & clean out your sea strainer. If it looks clean, momentarily open the seacocks to see if you get a good flow of water into the strainer. You might have sucked up something. Even if you find an obstruction to the water input probably a good idea to change the impeller as Jerry described.

Good luck, Art

 

[Rafiki]

Here's my variation of this one.....Onan 9KW generator, runs for fine at 60hz, 101 volts (should be 120, right?), at 23min voltage spikes to 130-140 a couple times, then at 25min engine shuts down nicely. Onan error code 12 - High AC Voltage; won't restart until cooled down; .......Strainer clean, good water flow; engine temp fine on scope; all fluids replaced, fuel filter replaced, voltage regulator replaced; load or no load no difference; 3 relays replaced, shutdown problem went away for a couple runs of 60min without shutdown, but returned a couple weeks later. Shutdown symptom seemed like a fuel problem (air in the line or flakey fuel pump?), but consistently low voltage with high spikes doesn't seem like fuel problem. Seems somehow heat related; I'm $2K in on diagnosis efforts and not even any good theories at this point. 3 different diesel mechanics say engine is fine, and electrician gave up; it's summer, argh!

Rafiki - 2007 SeaRay Sundancer 40

 

[Rafiki]

UPDATE - Thanks for your responses. Problem is solved. (Disclosure - I'm not mechanically inclined). After 3 mechanics couldn't figure it out...I went to the local Northwest CumminsOnan dealer and had a certified tech come to the boat. I should have done that first. He observed the low voltage 101 volts. He tested the generator windings for current/resistance and got good readings. He concluded the problem was voltage regulator. I said 3rd mechanic (electrician) had already replaced that ($for 400) and didn't solve problem. He had me show him what we replaced, and it wasn't the regulator. It was a 'second brain' (his words) which is a control panel on top of unit that connects to remote start switch and the Smartcraft remote on helm. He showed me the actual voltage regulator in the bottom front, replaced it, and problem solved. This is an Onan 9kw generator, 8 yrs old, 300 hours. Voltage regulator parts and labor for diagnosis and repair $1100. BOAT - bring out another thousand. Just in time for visitors and vacation!