Onan 5.5 Kw - Won't stay running and is blowing stuff up
Penny and Paul said
10:53 AM Dec 10, 2013
Our motorhome has a Onan Marquis 5.5Kv gas genset model 5.5BGMFA26105H. The PO didn't use it much so the hours are low for it's age. We've been using it as often as we can, and so far it had been working fine. This spring when we moved into the coach it wouldn't start, but our trusty local tech was able to get it going again. It worked well for a while and then one day it wouldn't start. On the third try it blew a breaker and a surge strip, and wouldn't stay running after the starter was released. Once we got where we were going, I tried to troubleshoot it, but just ended up blowing a higher capacity surge strip, a TV, and a controller for a mattress warmer. I can't find a manual for a model this old, and what I can find confuses me when I get to the stuff about exciter voltage and weird stuff like that.
We're heading up towards San Antonio in a week or two, and there are Cummins Onan dealers/service places there, but... Do I have it fixed? Do I replace it (it's a 1999)? Is this a common problem? Any thoughts?
TIA, Paul
-- Edited by Penny and Paul on Tuesday 10th of December 2013 10:54:46 AM
Lucky Mike said
11:43 AM Dec 10, 2013
you could have an Idle problem and it is racing......you could have a voltage rectifier problem.....Bottom line is unless you have the proper tools you could end up in hot water fast.
most rv shops can refer you to an onan servicer.....it is normally alot cheaper to repair it than replace it and a good tech should have it tuned and straightened out pretty fast!!......(the life of a genny is thousands of running hours)
GENECOP said
02:53 PM Dec 10, 2013
I have found many of the Cummins / Onan service places to be pretty good...they even have a Cummins Power club membership that pays for itself after one visit......good luck keep us posted...
Bill and Linda said
04:03 PM Dec 10, 2013
Paul:
Actually, 1999 isn’t all that old for a low hour gen set.We’ve used RV type generators in commercial service for over 20 years without issues except for normal maintenance.I’d take it to an authorized Onan - Cummins dealer / service center. Not just anyone so to speak. Unless the repair costs, which I doubt, are out of sight, a new one will be thousands of dollars and the old one, properly maintained, will work just fine for years.
As an aside, I would suggest you advise the dealer this unit hasn’t been used much.It most likely needs a complete fuel system cleaning in addition to some TLC maintenance.The trouble with gas units is the gas goes bad from lack of use in the generator fuel system and that leads to all sorts of unpleasantness even after you put in fresh fuel.. (For those interested - LP / Propane generators usually found in 5ers don’t have this problem and don’t mind “sitting around” like gas gen sets.They are less efficient, but usually a better choice in a 5er. Different situation in a motorhome. "It depends.")
Bill
Penny and Paul said
06:39 PM Dec 10, 2013
Looks like I need to see the Onan service guys up in San Antonio. Thanks everyone.
Lucky Mike said
06:44 PM Dec 10, 2013
Good luck Paul.....hopefully its something minor , quick and easy on the wallet!!
Our motorhome has a Onan Marquis 5.5Kv gas genset model 5.5BGMFA26105H. The PO didn't use it much so the hours are low for it's age. We've been using it as often as we can, and so far it had been working fine. This spring when we moved into the coach it wouldn't start, but our trusty local tech was able to get it going again. It worked well for a while and then one day it wouldn't start. On the third try it blew a breaker and a surge strip, and wouldn't stay running after the starter was released. Once we got where we were going, I tried to troubleshoot it, but just ended up blowing a higher capacity surge strip, a TV, and a controller for a mattress warmer. I can't find a manual for a model this old, and what I can find confuses me when I get to the stuff about exciter voltage and weird stuff like that.
We're heading up towards San Antonio in a week or two, and there are Cummins Onan dealers/service places there, but... Do I have it fixed? Do I replace it (it's a 1999)? Is this a common problem? Any thoughts?
TIA, Paul
-- Edited by Penny and Paul on Tuesday 10th of December 2013 10:54:46 AM
most rv shops can refer you to an onan servicer.....it is normally alot cheaper to repair it than replace it and a good tech should have it tuned and straightened out pretty fast!!......(the life of a genny is thousands of running hours)
Paul:
Actually, 1999 isn’t all that old for a low hour gen set. We’ve used RV type generators in commercial service for over 20 years without issues except for normal maintenance. I’d take it to an authorized Onan - Cummins dealer / service center. Not just anyone so to speak. Unless the repair costs, which I doubt, are out of sight, a new one will be thousands of dollars and the old one, properly maintained, will work just fine for years.
As an aside, I would suggest you advise the dealer this unit hasn’t been used much. It most likely needs a complete fuel system cleaning in addition to some TLC maintenance. The trouble with gas units is the gas goes bad from lack of use in the generator fuel system and that leads to all sorts of unpleasantness even after you put in fresh fuel.. (For those interested - LP / Propane generators usually found in 5ers don’t have this problem and don’t mind “sitting around” like gas gen sets. They are less efficient, but usually a better choice in a 5er. Different situation in a motorhome. "It depends.")
Bill