rvupgradestore.com Composet Products Fridge Defend
RV Life Magazine RV Park Reviews RV Trip Wizard

Author Topic: Onan generator stops after a few minutes  (Read 11175 times)

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #30 on: July 27, 2015, 11:20:16 PM »
did you try and rotate the bowl itself counterclockwise see if it unscrews? and yes inside the bowl your float and needle are probably gummed up. you should be able to blow thru the fuel inlet only holding the carb right side up and not while upside down.
Hi Sam!  If the bowl unscrews, it does so with more torque than I can muster with bare hands and rags.  Not sure what tool would help in that regard.  I definitely cannot blow air through the fuel inlet while the carb is right-side-up, nor does fluid (in this case, Sea Foam) drain from the inlet into the carb/bowl.  I have a 90 degree brass fitting in the inlet with the entrance upward so that I an pour cleaner into it and see if it drains, and it's doesn't...  Not yet, anyway.  Needle valve screw is still out.  Thoughts?
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #31 on: July 27, 2015, 11:25:20 PM »
Shown here is the brass fitting filled with Sea Foam going nowhere...
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Sam!

  • ---
  • Posts: 497
Re: Onan generator stops after a few minutes
« Reply #32 on: July 27, 2015, 11:39:53 PM »
put some compressed air in that. (without the fluid)

can i see a new picture of the bottom again with out the altitude needle?

1997 Serro Scotty 25' Diesel Cummins 4x4
2005 Dodge Ram 3500 Diesel SRW
2000 Tacoma Dezert trux
San Diegan

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #33 on: July 28, 2015, 08:22:18 AM »
Hey Sam.  I put compressed air in the inlet yesterday (120psi air hose) without fluid.  I'll try again today.  Here's a photo of the bottom of the carb with needle valve removed.
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Sam!

  • ---
  • Posts: 497
Re: Onan generator stops after a few minutes
« Reply #34 on: July 28, 2015, 08:27:19 AM »
there you go take that brass fitting off, that hold the bowl pressed up against the carb. that will expose the float needle and seat and main jet.
1997 Serro Scotty 25' Diesel Cummins 4x4
2005 Dodge Ram 3500 Diesel SRW
2000 Tacoma Dezert trux
San Diegan

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #35 on: July 28, 2015, 08:52:51 AM »
OK. What are the chances that I'll be trashing a big o-ring when I do that?  :)
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Sam!

  • ---
  • Posts: 497
Re: Onan generator stops after a few minutes
« Reply #36 on: July 28, 2015, 09:03:06 AM »
Cero
1997 Serro Scotty 25' Diesel Cummins 4x4
2005 Dodge Ram 3500 Diesel SRW
2000 Tacoma Dezert trux
San Diegan

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #37 on: July 28, 2015, 09:45:18 AM »
The bowl came right off in my hand, gasket intact.  And wow, you could grow plants in all the crud that's in here!  And it doesn't just look like dirt but rather some kind of sealant debris, like someone tried to use pipe sealer where the fittings came together.

The float doesn't "float" (move up and down) very easily, but I can't see why.  I removed it and pulled the needle valve from the fuel inlet hole and it had a chunk of crud in it, too, hence the cause of fuel starvation.

I'm going to hit this thing with some more Sea Foam then dry it all off with my air compressor, put it back together, and hopefully have a working generator today.  :)  I'll post more photos shortly.
« Last Edit: July 28, 2015, 09:47:19 AM by GemiNiveK »
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Charlie 5320

  • ---
  • Posts: 2121
Re: Onan generator stops after a few minutes
« Reply #38 on: July 28, 2015, 10:19:38 AM »
Use regular carb cleaner spray and compressed air. There are very small passages, they all have to be cleaned. Spray backwards through the seat and then blow it with air.

Make sure the float moves freely before you put it back together. Turn the carb upside down ant right side up the float should move freely when doing this.
« Last Edit: July 28, 2015, 10:24:34 AM by 92GA »
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #39 on: July 28, 2015, 11:16:30 AM »
Use regular carb cleaner spray and compressed air. There are very small passages, they all have to be cleaned. Spray backwards through the seat and then blow it with air.
Make sure the float moves freely before you put it back together. Turn the carb upside down ant right side up the float should move freely when doing this.

All inlets have been sprayed with carb cleaner and compressed air.  No particulate matter remains.  The needle valve that rides the float moves very freely in its chamber.  However, the float pivot seems to bind and I'm not sure why.  There's a strange, bent screw holding the pivot rod (photo attached).  This screw was pretty tight when I got into the carb, and I could only turn it about 90-120 degrees before it would bind up on the float since it's bent.  There's a dot in the head of the screw that corresponds with the direction of the bend.  The pivot rod is very easy to slide into and out of the float, so you would think that the float would pivot on it without having to turn the rod.  But as soon as this bent screw is secured against the rod, the float does not easily move.

Note that these photos were taken before the thorough cleaning activities, and they were taken randomly for the most part so they aren't necessarily the best views.
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Charlie 5320

  • ---
  • Posts: 2121
Re: Onan generator stops after a few minutes
« Reply #40 on: July 28, 2015, 11:23:20 AM »
Looks like the screw was over tightened and bent. Does the float drop when you put the carb upright? If it moves under it own weight when turning the carb it's OK.

It also looks as if the screw head is touching the float body. If it is sand a flat spot on the side of the screw where it is touching.

Also take out the brass screw next to the main jet and spay cleaner through that passage.
« Last Edit: July 28, 2015, 11:27:23 AM by 92GA »
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #41 on: July 28, 2015, 12:07:16 PM »
I just find it odd that the bend in the screw is exactly in the direction of that dot on the head.  It really seems intentional.  The screw definitely wasn't touching the float when I first pulled off the bowl.  The photo I uploaded with the rod removed has the screw turned with the float slightly moved and they are definitely touching...but that's not how it was originally.

The plot thickens...

The float spins very freely around the pivot rod when it is not mounted, so I know there's no binding between the two.  If I remove that screw completely and hold the rod in place manually, the float binds.  It is binding on the carb body itself as if it is swollen or otherwise a bit too wide to fit without significant friction on the sides...

Thoughts? 
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Sam!

  • ---
  • Posts: 497
Re: Onan generator stops after a few minutes
« Reply #42 on: July 28, 2015, 12:12:41 PM »
grab a file and clean up as needed all it needs to do is swing freely up and down. yes it can deform even from tightening the carb to motor.
1997 Serro Scotty 25' Diesel Cummins 4x4
2005 Dodge Ram 3500 Diesel SRW
2000 Tacoma Dezert trux
San Diegan

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #43 on: July 28, 2015, 12:28:55 PM »
grab a file and clean up as needed all it needs to do is swing freely up and down. yes it can deform even from tightening the carb to motor.
Done, and cleaned up all filings.  Re-installing this thing now and will let you know if I have a working generator shortly.  :)
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Charlie 5320

  • ---
  • Posts: 2121
Re: Onan generator stops after a few minutes
« Reply #44 on: July 28, 2015, 12:31:41 PM »
You have to make sure the float moves up and down under its own weight, if it's too tight file the sides a bit till it does. Not all things are manufactured right originally.
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #45 on: July 28, 2015, 01:01:48 PM »
You have to make sure the float moves up and down under its own weight, if it's too tight file the sides a bit till it does. Not all things are manufactured right originally.
Yep, that's what I had to do.  I filed the sides of the carb body until it the float moved up and down easily under its own weight.

I've reinstalled the carburetor and the GENERATOR IS RUNNING SMOOTHLY!  I had to fine-tune the bottom screw just a little (it was too lean).  I let it run with no load for 10 minutes then dialed it in a little tighter.  Then added one 13,500BTU roof air conditioner and let it run for 10 minutes then dialed it in a little tighter.  Then finally turned on the other roof air conditioner which should put it at nearly a full load.  Not sure if the mixture needs any more adjustment because it's running smoothly and the exhaust doesn't smell off.  No fuel leaks at any connections or at the bowl.  But I'm going to let it run for another 30 minutes or so with both air conditioners then check it again.

THANKS A MILLION for your insight and moral support, gentlemen!  Please let me know if you think of anything else I should be doing to ensure that this thing is running as correctly/efficiently as possible.

--Kevin
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Charlie 5320

  • ---
  • Posts: 2121
Re: Onan generator stops after a few minutes
« Reply #46 on: July 28, 2015, 01:07:52 PM »
If it's running smoothly loaded that's what your shooting for. Glad you got it going. Some say that the carbs can't be cleaned or repaired. You just proved they can be. Good luck, and make sure you do the run time every month to keep it clean. You might want to put one of those shut off valves like Sam mentioned, and run it out of gas for winter storage. I just unplug my fuel pump to do that. I have a 6600 Generac setup to power my house in emergency's.  ;D ;D ;D
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD

GemiNiveK

  • ---
  • Posts: 121
Re: Onan generator stops after a few minutes
« Reply #47 on: July 28, 2015, 02:17:55 PM »
By the way, THIS would-be sealant is the crap that was clogging up the carb (see photo attachment).  This is the brass elbow that was between the fuel filter and the inlet.  I replaced it.  I even found what looked like silicone gel form-a-gasket streaks running down into the manifold like someone tried to manufacture a gasket between it and the throttle body.  I suspect this poor genny went through hell at the hands of a mechanic who should have his/her wrenches revoked.  :\
« Last Edit: July 28, 2015, 02:32:03 PM by GemiNiveK »
I did it!  2000 Winnebago Brave WPF32T fully loaded with options!

Ready for new adventures, inside and outside of the RV, with and without the kids.
Young enough to get into trouble, old enough to know better, and fun enough to do it anyway.

Sam!

  • ---
  • Posts: 497
Re: Onan generator stops after a few minutes
« Reply #48 on: July 28, 2015, 02:40:42 PM »
glad you got your carb working and based on your finding is why I don't go recommending anyone that asks whats wrong with their genny to tear into the carb. the person that can do it will do it and like you ask about certain steps to proceed but will follow their gut (knowledge) and dive in.

thanks for sharing your findings and pictures.
1997 Serro Scotty 25' Diesel Cummins 4x4
2005 Dodge Ram 3500 Diesel SRW
2000 Tacoma Dezert trux
San Diegan

95Bounder32

  • ---
  • Posts: 12
Re: Onan generator stops after a few minutes
« Reply #49 on: August 19, 2018, 05:24:00 PM »
You have to pry the cap up so it clears . Make sure you count the turns so you can put it back.

Hello Charlie. When you say "You have to pry the cap up", are you referring to the "fin" that is sitting in the "groove"? As in I'd need to pry on the fin "A" to get it out of the groove "B" to unscrew it?

Charlie 5320

  • ---
  • Posts: 2121
Re: Onan generator stops after a few minutes
« Reply #50 on: August 19, 2018, 06:57:03 PM »
Hello Charlie. When you say "You have to pry the cap up", are you referring to the "fin" that is sitting in the "groove"? As in I'd need to pry on the fin "A" to get it out of the groove "B" to unscrew it?
Yes, you have to pry that cap up to be able to take that needle out. I'd mark the center so you know where to put it back on. Take the cap off, then turn it clock wise, and count the turns as you will need to put it back after cleaning the passage. Don't get too crazy tightening it down though, some of them are very small and can be damaged very easily.
Make sure you pry evenly on both sides till it comes loose.
« Last Edit: August 19, 2018, 07:05:35 PM by Charlie 5320 »
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD

95Bounder32

  • ---
  • Posts: 12
Re: Onan generator stops after a few minutes
« Reply #51 on: August 19, 2018, 08:47:51 PM »
Okay, so the altitude adjuster slider knob "fin" is what you are referring to as the "cap", got it. Thank you.

Have a look at this video. Safe to say the float is stuck?

https://youtu.be/uA3MpYwGFIs

Charlie 5320

  • ---
  • Posts: 2121
Re: Onan generator stops after a few minutes
« Reply #52 on: August 19, 2018, 09:14:19 PM »
Okay, so the altitude adjuster slider knob "fin" is what you are referring to as the "cap", got it. Thank you.

Have a look at this video. Safe to say the float is stuck?

https://youtu.be/uA3MpYwGFIs

Yes, it has to be in the most open position to get that much gas. The pump only has a couple lbs of pressure but will flow a lot of gas.

Some carbs don't have the altitude adjuster, but that's what it is, it just cuts or adds just a bit of fuel. It has a limiter so you can't go too far with it. Make sure you have it in the correct position before you put it back on.
« Last Edit: August 19, 2018, 09:18:26 PM by Charlie 5320 »
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD

95Bounder32

  • ---
  • Posts: 12
Re: Onan generator stops after a few minutes
« Reply #53 on: August 19, 2018, 11:07:14 PM »
10/4. Thanks, Charlie! I have to go out and buy some stubby wrenches with an angled head on them to get to the two carb nuts. Once I gather those and make time to do the procedure, I let you and everyone else know what the scoop is... Thanks again!

95Bounder32

  • ---
  • Posts: 12
Re: Onan generator stops after a few minutes
« Reply #54 on: September 16, 2018, 06:01:52 PM »
I removed the carb and opened it up. The needle looked pristine, the float action was just fine, the bowl was very clean. I disassembled the float and cleaned all ports. I put it back together and reinstalled it. The generator started up no problem and purred like a kitten... For about 30 seconds and then died. Tried to restart it and voila... the SAME THING! :banghead: Any ideas folks? Is the pressure too high causing the needle to unseat?

Old_Crow

  • ---
  • Posts: 892
  • Former Phantom Fixer
Re: Onan generator stops after a few minutes
« Reply #55 on: September 17, 2018, 08:24:28 AM »
Not sure what the float is made out of, but brass floats can get holes in them and the composite floats can become saturated with fuel and not float any more. 
Wally Crow
Retired 30 year ASE Master Auto Tech
Y2K Bounder 36S F53
'03 Jeep Wrangler Sahara

Charlie 5320

  • ---
  • Posts: 2121
Re: Onan generator stops after a few minutes
« Reply #56 on: September 18, 2018, 07:27:29 PM »
You have to determine if your problem is fuel or electrical. If it starts and shuts right down every time it may be electrical. Some onans won't run if it's not making power. You will need to get on line and find a trouble shooting guide to go by. I haven't worked on enough onans to be able to tell you which ones will run and the ones that won't run if they're not making power.
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD