Onan Starting Issues

LazyDog · 11-29-2006, 04:33 AM

Here's a weird one to tease the brain!

I have an Onan Emerald Plus 6500 gas generator. Purchased the rig in the fall of 2005 and have added just over 50 hours of geny time to bring the total to 380. As part of my fall maintenance I changed the oil and filter. Using an Onan filter and moved to a synthetic 10W-30 oil since I had read so may positive comments.
With the job complete I ran the generator to circulate the oil and after 5 or 6 minutes it shut itself down. I was not able to restart it however it starts and runs as long as I hold the toggle in the START position. As soon as I release it, it shuts down. The only thing I could determine was that perhaps I had added too much oil in refilling so I drained the oil to the bottom of the ADD mark - the generator started on the second crank. I added enough oil to bring it to 1/2 on the dip stick and considered the issue solved!
A week later, the same issue. Starting with the toggle held and shutting down when released. Drained the oil to below the add mark and away it went! Once started everything appears to function properly and no shutdown after 15 minutes of running. Also restarts repeatedly with no hesitation. The rig is level and the generator was working fine before the oil change. I suspect the LOW OIL level switch is faulty but don't think getting to it is something I want to tackle outdoors in a Canadian December. I can identify a single white wire running over the top of the oil reservoir and so assume that's the connection to the switch I see on the schematics. It runs into the control panel on the generator itself. Anyone care to offer a suggestion on whether I should open up the panel and see if I can disconnect this wire to see if this is my issue?

Any other ideas on what has gone wrong? I'm considering changing back to Dino oil to see if that makes a difference but the $8(American) filter goes for just over $20(Canadian)here in Ontario!

Thoughts??

LazyDog · 11-29-2006, 04:33 AM

Here's a weird one to tease the brain!

I have an Onan Emerald Plus 6500 gas generator. Purchased the rig in the fall of 2005 and have added just over 50 hours of geny time to bring the total to 380. As part of my fall maintenance I changed the oil and filter. Using an Onan filter and moved to a synthetic 10W-30 oil since I had read so may positive comments.
With the job complete I ran the generator to circulate the oil and after 5 or 6 minutes it shut itself down. I was not able to restart it however it starts and runs as long as I hold the toggle in the START position. As soon as I release it, it shuts down. The only thing I could determine was that perhaps I had added too much oil in refilling so I drained the oil to the bottom of the ADD mark - the generator started on the second crank. I added enough oil to bring it to 1/2 on the dip stick and considered the issue solved!
A week later, the same issue. Starting with the toggle held and shutting down when released. Drained the oil to below the add mark and away it went! Once started everything appears to function properly and no shutdown after 15 minutes of running. Also restarts repeatedly with no hesitation. The rig is level and the generator was working fine before the oil change. I suspect the LOW OIL level switch is faulty but don't think getting to it is something I want to tackle outdoors in a Canadian December. I can identify a single white wire running over the top of the oil reservoir and so assume that's the connection to the switch I see on the schematics. It runs into the control panel on the generator itself. Anyone care to offer a suggestion on whether I should open up the panel and see if I can disconnect this wire to see if this is my issue?

Any other ideas on what has gone wrong? I'm considering changing back to Dino oil to see if that makes a difference but the $8(American) filter goes for just over $20(Canadian)here in Ontario!

Thoughts??

Dsouthw524 · 11-29-2006, 06:35 AM

I suggest you contact Onan for their input. They are usually responsive. Their web site is:
www.onan.com/onan/service/serviceHome.jsp

peter griffin · 11-29-2006, 07:50 AM

i believe it is the oil..go back to standard oil.....if you perform maintenance and run the generator...monthly it should last a long time...also i bet onan tells you not to run synthetic...

full-timer · 11-29-2006, 09:12 AM

If you don't want to buy another filter,I would just take it off and let it drain for awhile and use the same filter. I don't think with the little amount of oil that is left in the filter will make a difference.

Joe

Marty & Yani · 11-29-2006, 12:50 PM

It's not the Synthetic oil, I use it in my Onan Emerald 5500 gas Generator without any problems.
Marty

bflem · 11-29-2006, 01:22 PM

I dont think it is the oil. It sounds like a voltage regulater has gone bad. The voltage is supplied from the coach battery when the switch is held down and by the generater when it is released.

rick_od · 11-29-2006, 04:41 PM

This past weekend I went to start my Onan 4000. It hadn't been run for a couple of months. It to would start and run until I let go of the start switch. To my supprise...my coach is plugged into the house and the Onan was connected to nothing. When I pluged the coach into the Onan (which had a load as my batteries needed to be charged) the Onan ran perfect. Go figure???

LazyDog · 11-30-2006, 05:42 AM

Thanks to All for your input!

rick_od - I wondered that at one point too. Tried it with the coach connected to the geny and without - didn't seem to make the difference.
bflem - would the voltage regulator fail intermittently? I presume then, you are suggesting a coincidence that it seems to work when I drain the oil but not when I don't?
This is an interesting point because now that I think about it, if I attempt to start the Geny from the dashboard switch, the green light(indicating generator running) within the toggle doesn't glow, even when I hold it in the start position. Memory suggests that in the past the light would glow and go out if the generator didn't start on the first crank.

Mmmm... the plot thickens!

Any other thoughts/input??

gunny · 11-30-2006, 01:38 PM

Rich:
No, voltage regulators rarely heal themselves. I doubt that is the problem.

My theory on this is that the additives in the synthetic are having a little problem with what is left of the old oil and causignthe oil to foam. Foamed oil doesn't hold pressure well and also doesn't lubricate well either. It doesn't hurt to run the engine with the oil level on the low side, just don't run it out. Try it and see. By the way Onan uses a low oil pressure shut down, not a level sensor.

The remote switch pilot light not working....might be just a burned out bulb, loose connection. Possible that it is related but don't think so.

zertrider · 11-30-2006, 05:07 PM

Drain the oil and put in 15w40 or straight 30 and your problem will be solved. To find out for sure, just disconnect the oil pressure switch and jump it to ground. if the genny runs non stop, you know the wrong oil is in it. If you read your manual for the unit, it will tell you to run 15w40 for most temperature conditions.On the older Emerald 6500 they may have even suggested 30 weight. Only go lighter than that if you plan on using it in VERY cold conditions.
So go ahead, run synthetic, but in the right weight.

Marty & Yani · 11-30-2006, 07:48 PM

Onan has a low pressurs senser and a low oil senser, if the MH is not level and the gen set is low on oil this could be a problem. As for foam the oil pick up is in the bottom and would not pick up foam, also syn oil does not foam if mixed with dyno oil they are compatable with each other. As for oil weight 15-40 is best, but 0-30 would work also.
Marty

LazyDog · 12-01-2006, 05:10 AM

OK Fellas

Friday's here so this weekend I'll switch out to 15-40 and see what happens!

Zertrider
To disconnect and ground the pressure switch are you suggesting I pull open the control panel and follow back that white wire I mentioned? Is this where the wire would terminate in order to shut the unit down in the event of a 'low' condition (pressure/volume)?

Man, I thought I was doing a good thing in switching to the synthetic. Right about now I'm wishing I had saved my money and stuck with the Dino oil!

peter griffin · 12-01-2006, 05:33 AM

dont play with all those wires...just change the oil and run the generator and sit back and relax and enjoy! keep us posted....

zertrider · 12-01-2006, 12:41 PM

Taking the cover off of the control panel is very easy and yes the wire from the oil pressure switch has a connector behind that cover. But forget about trying that and just switch the oil to 15w40 and try it. Should run like it used to.

Scratch & Goose · 12-01-2006, 01:12 PM

Hello
I can well asure you it's not he type oil youre useing that causing the problem.
I changed my unit to syn Moble 1 10W30 the first week I got it, 46 hrs old....
Maybe reread your gen manual, contact the mfg. try dong an OHM test to ground, maybe it shorted somewhere...
Scratch

Pubtym · 12-01-2006, 02:35 PM

I am using Walley Syn 5/30W. No problems in single digits (South Dakota). Starts perfectly!

zertrider · 12-02-2006, 05:08 AM

Goose and Pubtym, you are both talking about relatively new generators, on very different models . I would guess that both of you have a newer model such as a Marquis 5500. On the previous generation units such as the Emerald, they were very sensitive to using anything but 15w40 or straight 30 weight. Compare apples to apples. And he has a unit that has many more hrs on it than yours and may not build as much oil pressure due to some wear.
Again, read your owners manual, it will tell you which grade of oil to use for specific conditions.

DCudmore · 12-02-2006, 02:36 PM

Your oil is to light and will not hold the pressure so the engine shuts down just like it would with low oil. I believe if you check with your book it will say 30W oil for that engine,,Some do use the 15-40 as well..10-30 and so on is just to light.

gunny · 12-03-2006, 03:37 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Marty & Yani:
Onan has a low pressurs senser and a low oil senser, if the MH is not level and the gen set is low on oil this could be a problem. As for foam the oil pick up is in the bottom and would not pick up foam, also syn oil does not foam if mixed with dyno oil they are compatable with each other. As for oil weight 15-40 is best, but 0-30 would work also.
Marty </div></BLOCKQUOTE>
0-30 oil? In what temperature range? Be pretty light if the temperture gets above freezing.
The original poster did not post the generator model/spec/serial number so how do you know it has a low level and pressure sensor?
Oil can foam to the point of it all being foam. At that point it doen't make any difference where the pick up tube is, all you then get is foam.

By the way....Amsoil is NOT API certified and should you have a lubrication issue, you may be disappointed when it comes time for warranty to step up to the plate. Some manufacturers will do anything to deny a warranty claim.