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Generac generator rums then dies

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Ice forecast here for tonight, and an older couple asked if I would get their generator out and make sure it would start. 

 

Last time they used it I told the husband to run it dry before he put it up and he did so.

 

 Fresh gas, started right up with a couple of pushes on the bulb on the carburetor, but then runs for 10 to 15 seconds and dies. 

 

I messed with it for awhile. Carb looks clean. Main jet is clear. After awhile I came to the conclusion that it seems to be losing spark. The last few times it actually appeared fuel was being blown back out of the carb.

 

Plug looks good

 

Oil is full but I’m thinking the oil pressure switch might be bad. 

 

Anyone have any other ideas? 

 

If the power goes out I’ll be on it again in the AM

 

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I think if the oil switch were bad or the oil low , then it wouldn't start at all ---  would think fuel problem 

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Can you bypass the low oil switch (if it has one) to rule it out? I haven't worked on many generators, they are not used much around here.

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i go along with oil switch, going bad, being it runs fine for a short time. but sneezing back out of the carb ? and this happened while you were trying to start it, or when it was running (for those short times ?) was it running fine the last time they used it ? 

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Ran fine last time they used it, but it’s been awhile (year or two)

 

Sneezed gas out of the carb as it died. 

 

No fuel pump, just a little gravity feed carb. 

 

We didnt get a tremendous amount of ice, so they shouldn’t need it. I still need to get it going for them, but at least I won’t be rushed 

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9 hours ago, Fishfiles said:

I think if the oil switch were bad or the oil low , then it wouldn't start at all ---  would think fuel problem 

 

Found this a few mins ago, which really leads me to believe it might be the oil switch 

 

 

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That's different having a oil pressure sensor --- I always been a Honda or Briggs guy and have oil level switches  

 

Looked to see what brand engine Generac uses on their 4000 , it says Engine Generac , doubt that , looks like a Briggs OHV built to Generac specs, or maybe a Subura/ Robin 

 

 

Glad you figured it out , I would leave it unplugged , but being it is for your elderly neighbor ---  but then again , after watching the video and seeing all the other videos with the same problem , maybe best to leave it unplugged and tell them to check the oil 

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Must be a low pressure pump.  Don't believe that engine would have plain bearings....but you never know.  Be nice to plug a gauge in that hole and see what it reads.

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had a problem with my honda this past season...just couldn't keep it running..even replaced the carb...turned out...fuel line had a slit in it..sucking are...bad when cold on choke, worse/complete kill once things got warmed up...I'd check all those old fuel lines before digging too deep into the machine itself.

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with it being a stationary unit that  is meant to run all night un attended it's likely a pressure switch, then an oil level switch , where as on Mobil units like mowers, that are used (sometimes) on un level ground where oil can move to one side (away from the level switch) thats how my wood spitter is, it's got to be level when running, or it won't even try to start, i was also thinking maybe the one he has may need a oil filter change (if it has one.) toombs brothers dairy had a cummins power slurry pond pump, that acted the same, and it was a low oil pressure switch. but in that case it was a defective oil pressure switch. 

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Is it running with a load on it? All my generators will die just like that if they arent being put under electrical load. After you put it under load you can flip the switch and it will stay running constant. Cont recall what the switch says at the moment. But i was shocked when i saw the start and run procedures for some of these things.

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On my Honda knockoff generator my switch says Idle Control, it does die down to idle when on but has never died.....

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9 hours ago, bcsman said:

On my Honda knockoff generator my switch says Idle Control, it does die down to idle when on but has never died.....

That's a nice feature to have , I guess I would call it ,  On Demand Throttle Control , ex :n if you were a construction worker using a power tool , when the tool was trigger the throttle would kick up and the tool runs , let go of the trigger and it goes back to idle , saves noise , fuel and wear 

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Yep thats how it works, quieter too when no demand is there....plus saves some fuel

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15 hours ago, SlammedRanger said:

Is it running with a load on it? All my generators will die just like that if they arent being put under electrical load. After you put it under load you can flip the switch and it will stay running constant. Cont recall what the switch says at the moment. But i was shocked when i saw the start and run procedures for some of these things.

I was going to ask that same question but I got the impression that it's a unit they've used in the past...  it was something that caught me by surprise with my latest genny...I'd crank it and a couple mins later it would die...had me cussing for a couple times, til it dawned on me that it might want a load... plugged a small light into it and it  ran happy for 30 mins.....my old honda eu2000 doesn't care...you crank it, let it run...the end.

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I've had to clean this one up in the past, and I don't recall ever having a load on it when I had to clean the carb in the past. 

 

Still freezing cold here, so I haven't been back over to check it again.  I might try to do so tomorrow.  Supposed to be bitterly cold and start snowing Sunday/Monday now.

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7 hours ago, Fishfiles said:

That's a nice feature to have , I guess I would call it ,  On Demand Throttle Control , ex :n if you were a construction worker using a power tool , when the tool was trigger the throttle would kick up and the tool runs , let go of the trigger and it goes back to idle , saves noise , fuel and wear 

 

steve has an old gas power ac/dc welding setup, that acts just like that, strike an arc, and the rpm goes up, stop, and it drops, reference the link. 

 

https://m.youtube.com/watch?v=89I900o-zlE

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9 minutes ago, _Wilson_™ said:

 

steve has an old gas power ac/dc welding setup, that acts just like that, strike an arc, and the rpm goes up, stop, and it drops, reference the link. 

 

https://m.youtube.com/watch?v=89I900o-zlE

My welding machine on my truck use to do the auto idle thing , but when it broke , pulled it back in the  run/weld mode all the time now with some stainless tie wire  ---- stainless is a permanent repair , eh 

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57 minutes ago, _Wilson_™ said:

 

steve has an old gas power ac/dc welding setup, that acts just like that, strike an arc, and the rpm goes up, stop, and it drops, reference the link. 

 

https://m.youtube.com/watch?v=89I900o-zlE

yep...the  honda eu series all do that...there's a switch..you can select to have it run WOT all the time, or it can go on efficient mode...where it idles down nice n low..very quiet...doesn't even budge  off idle when I have it running the TV and fan in the camper, but fire up the microwave and that puppy throttles up til the demand is off...better gas run time, quiet as possible, etc...

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52 minutes ago, Fishfiles said:

My welding machine on my truck use to do the auto idle thing , but when it broke , pulled it back in the  run/weld mode all the time now with some stainless tie wire  ---- stainless is a permanent repair , eh 

We had a diesel welder that we started and ran ay -45C, welded one section welder quit never ran again.....😆 🤣

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Well I did manage to swing by yesterday after church.  Unhooked that sensor and it cranked up and ran like a top until I shut it off manually.

Doubt they'll need it since we're getting snow tomorrow again on the 8" we got last night, but at least it will work if they need it.

 

Interestingly enough I lost power last night for a while.  Transformer blew.   Was only out for about 5 hours, but during that time the temp dropped to the upper 50's in the house.  We were next door eating at the parents' when it blew, so at least we were warm waiting on them to fix it.

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good deal, i reckon the carb, sneezing didnt have any effect, i didn't know y'all had that much snow, so far it's just been a dusting here IMO, but the cold grip will make things very interesting, we've been lucky (if one could be) over this mess.  

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