onan

g1g · 08-27-2014, 12:59 AM

Well I just got back from the Black Hills and everything was beautiful. The genny was running better than ever until the last day it would crank over great and start but as soon as I let go of the start button it dies. Any idea on what could be wrong? it is a 1994 Onan 2.8 KW

gerrym51 · 08-27-2014, 04:08 AM

Quote:

Originally Posted by g1g

Well I just got back from the Black Hills and everything was beautiful. The genny was running better than ever until the last day it would crank over great and start but as soon as I let go of the start button it dies. Any idea on what could be wrong? it is a 1994 Onan 2.8 KW

did you check the oil. onan will keep shutting off when low on oil.

markopolo · 08-27-2014, 01:24 PM

I was thinking the same as Gerry.
Next would be to make sure there is enough gas in the van tank for the Onan pickup. Usually at least 1/4 tank is needed. One forum member posted that his needed 1/2 tank and he reinstalled the pickup tube to work until approx 1/4 tank.
After that it would be checking electrical connections. Then fuel pump etc. But low oil would cause the symptom you describe.

g1g · 08-28-2014, 02:37 AM

I was reading the troubleshooting guide after I posted and it mentioned low oil so just checked it and it is full. I dd change it about 8-9 hours run time with Mobil 1. I tried it again and still dies when I let go of the switch.

markopolo · 08-28-2014, 12:18 PM

I read through some Onan Troubleshooting.
For "Engine starts but stops when start switch is released" #1 is low oil and #2 is "Defective low oil level switch"

Instructions for #2 are: "Disconnect low oil level switch and check set operation. Replace if defective"

booster · 08-28-2014, 04:00 PM

Quote:

Originally Posted by markopolo

I read through some Onan Troubleshooting.
For "Engine starts but stops when start switch is released" #1 is low oil and #2 is "Defective low oil level switch"

Instructions for #2 are: "Disconnect low oil level switch and check set operation. Replace if defective"

This does seem to be a fairly common failure, based on what shows up on the Yahoo board. IIRC, the control board is often at fault, and a relay on it gets bypassed when the button is pushed so it will run with the button pushed. Oil level switch also, and much easier to check out.

Barman · 09-06-2014, 02:53 AM

I sure hope that you have better luck finding your issue with it than I did. I started calling ours a ghost. For almost a year there would be days that it would start normal and run great no complaint. Then out of the blue it would only run while the switch was depressed, and quit as soon as you let go of the switch. We even had a Cummings Onan service shop pull the generator and trouble shoot. They replaced the starter relay, and total bill was $1400.00. Mostly labor because the relay was only $65.00. Three days later it was doing the exact same thing again. This continued for months where I would try and start it, and sometime it would, and sometime it would not. Finally this summer I pulled it myself, and tried inspecting all I new with no luck. I drove to a different Cummings facility a dropped it there with a lengthy letter of what all had been done, and told them it was not reliable, and I needed it to be, and do some real diagnostic checks please, and call me when they found something. In a nutshell they determined that the generator needed a new rotor assembly at ($351.1

, voltage regulator ($239.7

, valve cover gasket, brushes ($15.04), and rotor bearing o-ring. All totaled they were going to charge me $1700.00 for everything. Well we had just put $1400.00 in it in February, and now another $1700.00. And the killer was they only give a 90 day warranty. Well we thought it all out and decided against having $3100.00 invested in our 9 year old generator, and only have 90 days to make sure all was ok. I ordered a brand new 2800, and it cost me $2152.00, and has a 3-year warranty. I think it was the right decision for us, but it has not been without its issues either. The brand new units are not exact matches. The dimensions of the cabinet are different, and all of the fuel, electrical and exhaust hookups are in totally different places. So it has required me re-engineering a new way to install it all. I have managed to get everything finished now except the exhaust pipe. What a night mare, it is 1 1/8 inch OD tube and absolutely no one has dies that size I have found. I have managed to run the new system with a temporary exhaust setup, and it is smoother, quieter, and I do like it. After I manage to get the exhaust pipe issue resolved I really think it will all be fine, but unless the person doing this project has plenty of fabrication skills, I would not recommend taking the route I did. I really hope that you have better luck with yours. They were very thorough on their diagnostics though, and they felt the items I quoted above were the root of the problem, so you may be looking at rotor, voltage regulator and brushes problems. Best of luck finding the problem and getting your rig back in service.

Deano · 10-10-2016, 05:18 AM

FWIW, The Onan folks I spoke with do not recommend synthetic oil in the 2800 generator.
Something about it does not have an oil filter, so they recommend conventional oil.

g1g · 10-11-2016, 10:54 PM

[QUOTE=Deano;49222]FWIW, The Onan folks I spoke with do not recommend synthetic oil in the 2800 generator.
Something about it does not have an oil filter, so they recommend conventional oil.[/QUOTE

I generally change my oil at the same interval that you would change regular oil

mojoman · 10-11-2016, 11:25 PM

Any air-cooled engine benefits from using synthetic oil due to the ability of the oil to perform better in high heat. I use royal purple full synthetic in mine since it only uses one quart.

Deano · 10-11-2016, 11:32 PM

OK, Here is the entire email.

From: Kevin D Pierce [mailto:kevin.d.pierce@cummins.com]
Sent: Thursday, August 13, 2015 5:52 AM
To: dmaycock@q.com
Subject: Oil Recommendations (2.8KV-FA/26100K)

Good morning! I’m sorry it’s taken me as long as it has to respond, I have tried to be as thorough with your request as I can.
I have checked with technicians, service supervisors, and even one of our DFSE’s (Distributor Field Service Engineer) and they all recommend NOT using synthetic oil in this application.
This model does not have a pressurized lubrication system (no oil pump) and therefore also does not have an oil filter.
Synthetic oils are heavily reliant on oil filtration to remove dirt and other impurities.

I have attached a copy of the Oil Recommendations from the Owner’s Manual for this model, which I feel you already have a copy of, (this is all I can find for this application).

Please let me know if you have any questions or if I can be of further assistance!

Thanks, Kevin

Kevin Pierce
Parts Manager
Military Sales Specialist
Cummins Power South, LLC
1915 W. Oakridge Drive
Albany, GA 31707
(229) 888-6210 ext 6214
(229) 883-1670 fax
(229) 376-5712 cell
Kevin.d.pierce@cummins.com
Cummins Power South, LLC

mojoman · 10-12-2016, 12:45 AM

So non synthetic oils are not as reliant on oil filtration to remove dirt? Doesn't make sense. I think the reason for not recommending synthetic oil oil is the perception it will last longer, having no filter means frequent oil changes with any type of oil used, where as in a filtered system the synthetic oil will provide longer service life.

booster · 10-12-2016, 12:53 AM

Quote:

Originally Posted by mojoman

So non synthetic oils are not as reliant on oil filtration to remove dirt? Doesn't make sense. I think the reason for not recommending synthetic oil oil is the perception it will last longer, having no filter means frequent oil changes with any type of oil used, where as in a filtered system the synthetic oil will provide longer service life.

I think what Onan is doing is discouraging synthetic oil use because they think people will believe the hype about doubling the time between oil changes. To get the huge increase in change intervals, you need to have a micron bypass filter with synthetic exactly because contamination doesn't care what kind of oil you use.

I would not hesitate to use synthetic in an Onan (we did when we had one), but you just need to change it at the recommended intervals. You will not get extended times, but you will get easier cold starts, and high temp protection, so you still get benefits.

Deano · 10-12-2016, 02:08 AM

Could it be they are correct based on information we don't have. They certainly would want their product to be reliable. So to me it stands to reason they would recommend what they believe will give the best reliability.

booster · 10-12-2016, 02:21 AM

Quote:

Originally Posted by Deano

Could it be they are correct based on information we don't have. They certainly would want their product to be reliable. So to me it stands to reason they would recommend what they believe will give the best reliability.

IMO, not really likely. What is more probable is that they recommend the oil that they have had for a long time, that is not synthetic. I worked for a pump company that said the same thing for many years, "don't use synthetic only use our private labeled dino oil". But as soon as they came out with their own synthetic private label oil, they had a whole list of wonderful benefits to justify the higher price. Am I a skeptic when it comes to trusting manufacturers to give you the accurate information, absolutely, as I have been on the inside of all of that kind of stuff for many decades.

You may also like: