Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > MH-General Discussions & Problems
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 06-19-2017, 10:34 AM   #1
Senior Member
 
Kahoona's Avatar
 
National RV Owners Club
Freightliner Owners Club
Join Date: Jul 2015
Location: Conch Republic
Posts: 2,495
Onan 4K won't run unless the start button is kept on.

Hi
I have an Onan Microquiet 4k. It is a KY type Spec J. It starts fine but shuts down abruptly as soon as the start button is released. It doesn't stumble and die slow but shuts down immediately. This seems to be a common problem. It ran when I exercised it 2 weeks ago but it shut down on it's own. It has always done that once in a while. I went to start it recently and ran into this problem. Here is what I know.

Fuel supply is good. I tested it.

Plenty of oil.

Batteries good

No error codes.

No gnawed wires visible from the front. I removed the board and checked beneath too.

Air cleaner good.

Fiddling with the governor and choke make no difference.

I have been to the Flight Systems Inc site and checked their troubleshooting area but it states that this model (KY, Spec J) is not included because of a microcomputer. The problem is that it could be brushes inside, a bad sensor, the voltage regulator or something else. I'd like to narrow it down so I don't have to try drop the box in the driveway or replace the board without knowing if it's bad. Does anyone know where I can get testing info? It is interesting that the board is submerged in a block of some sort of plastic. Good idea since it is exposed to all sorts on nastiness but it makes it hard to examine.
__________________
33' 2008 National Tropical on a Freightliner chassis.We tow a 2001 XJ (Cherokee) RVM#189
Kahoona is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 06-19-2017, 10:55 AM   #2
Senior Member
 
powderman's Avatar
 
Join Date: Mar 2010
Location: N. E. Ohio & Lady Lake Fl.
Posts: 1,120
I can't say this is your problem, but some of the older Onan 4k's had a resister in the start circuit. The idea was to provide full battery voltage to start and when the button is released, the resister was used to drop the voltage when running to save the ignition when running. If the wire wound resister goes bad the circuit opens and does as you described. Get a schematic and see if yours uses it. Its a cheap fix once you get to the resister hidden behind the fuel pump. Good luck.
__________________
Ron WD8CBT

I started out with nothing and I still have most of it left
powderman is offline   Reply With Quote
Old 06-19-2017, 11:04 AM   #3
Senior Member
 
Kahoona's Avatar
 
National RV Owners Club
Freightliner Owners Club
Join Date: Jul 2015
Location: Conch Republic
Posts: 2,495
Quote:
Originally Posted by powderman View Post
I can't say this is your problem, but some of the older Onan 4k's had a resister in the start circuit. The idea was to provide full battery voltage to start and when the button is released, the resister was used to drop the voltage when running to save the ignition when running. If the wire wound resister goes bad the circuit opens and does as you described. Get a schematic and see if yours uses it. Its a cheap fix once you get to the resister hidden behind the fuel pump. Good luck.
Thanks. I am afraid I have had everything on that side out last year when I replaced the fuel pump, and filter and mine does not have one. Thanks for taking the time though.
__________________
33' 2008 National Tropical on a Freightliner chassis.We tow a 2001 XJ (Cherokee) RVM#189
Kahoona is offline   Reply With Quote
Old 06-19-2017, 11:37 AM   #4
Senior Member
 
powderman's Avatar
 
Join Date: Mar 2010
Location: N. E. Ohio & Lady Lake Fl.
Posts: 1,120
Try this link to PDF and refer to 6-9

https://www.google.com/url?sa=t&sour...3Nh1JxbJVT32Bw
__________________
Ron WD8CBT

I started out with nothing and I still have most of it left
powderman is offline   Reply With Quote
Old 06-19-2017, 12:14 PM   #5
Senior Member
 
Kahoona's Avatar
 
National RV Owners Club
Freightliner Owners Club
Join Date: Jul 2015
Location: Conch Republic
Posts: 2,495
Quote:
Originally Posted by powderman View Post
Try this link to PDF and refer to 6-9

https://www.google.com/url?sa=t&sour...3Nh1JxbJVT32Bw
This is wonderful. Thanks. Yes. That page shows the possible problems. I have to find out which it is. Hope it's not slip rings because I'd have to remove the generator. I am hoping that this


Control – Spec A models (page 6-4)

Control – Begin Spec B models (page 6-16


means that spec B an onward are covered. I have a Spec J and it looks similar but not exact. I hope that is covered. I am hoping that with these diagrams I can go some testing with a meter using that plug that goes into the board and see where the problem lies. Thank you. This may be what I need. I'll study it and let you know what I find.
__________________
33' 2008 National Tropical on a Freightliner chassis.We tow a 2001 XJ (Cherokee) RVM#189
Kahoona is offline   Reply With Quote
Old 06-19-2017, 01:01 PM   #6
Senior Member
 
Kahoona's Avatar
 
National RV Owners Club
Freightliner Owners Club
Join Date: Jul 2015
Location: Conch Republic
Posts: 2,495
Powderman: Quite a bit there to figure out but I believe it has what I need. I want to clean up the harnesses especially those dealing with sensing the voltages and check for bad connections or mouse gnawing. I may be a couple of days because I am also repairing the AC. Thanks again.

Question for all- Can I remove the fan on the intake without causing any problems. I want to use a mirror to see if I can see the brushes and rings to check them. There is a nut on the end but it is on the main shaft.
__________________
33' 2008 National Tropical on a Freightliner chassis.We tow a 2001 XJ (Cherokee) RVM#189
Kahoona is offline   Reply With Quote
Old 06-19-2017, 10:47 PM   #7
Senior Member
 
Join Date: Feb 2010
Posts: 4,654
A few suggestions and follow up on previous posts.

Either one could be loose wire so review the manual for these and how to test as you may get off easy.

Point and coil ignition for 12 volt engines are really a 6 volt or so coil.

This is to have greater spark when cranking the engine as the battery voltage is lower at this time.

There is a voltage dropping resistor in circuit to the ign switch to drop the voltage while running and another wire from the starter circuit that applies battery voltage to coil.

Open resistor or loose connection will cause this as the start circuit is direct connection.

Test by locating coil or points then with points open check voltage with key on.

If it has a kill switch that point works or check manual.

Should be voltage present with key on...unless...interlock broken...

Many engines have a switch in the oil system that opens up with oil pressure.

When closed it shorts points to ground killing ign.

This is low oil switch...but to start engine there is no oil pressure unless running...There is usually an interlock to the starter circuit that bypasses this switch while starter is in start mode.

When the interlock fails it only runs when starter is on.
__________________
Tony & Lori
1989 Country Coach Savannah SE
TQ60 is offline   Reply With Quote
Old 06-20-2017, 07:20 AM   #8
Senior Member
 
Kahoona's Avatar
 
National RV Owners Club
Freightliner Owners Club
Join Date: Jul 2015
Location: Conch Republic
Posts: 2,495
Thanks TQ60 I will go over those things today.

I asked Advanced Service if there is a simple way to test brushes and Slip rings before buying a board and they said"

Yes, you can test the resistance (ohms) between the slip rings. Once you do that, send the reading and generator model number to us. We'll be able to tell you if the rotor is good or not with that info.

Thanks,
John Martin
Advanced Service And Parts, LLC

This sounds like something I can do with the genny in place if I can determine where to test. I am hoping that this is in the plug from the board. Anyone done this?

I'll study the manual and work on these things later today and report back.
Thanks vary much I appreciate the help greatly.
__________________
33' 2008 National Tropical on a Freightliner chassis.We tow a 2001 XJ (Cherokee) RVM#189
Kahoona is offline   Reply With Quote
Old 06-20-2017, 07:31 AM   #9
Senior Member
 
Unplanned Tourist's Avatar
 
Winnebago Owners Club
Workhorse Chassis Owner
Join Date: May 2016
Location: Kamloops, BC, 60 miles from the Center of the Universe according to the Rinpoche, of the SF monks.
Posts: 7,321
Quote:
Originally Posted by Kahoona View Post
Hi
I have an Onan Microquiet 4k. It is a KY type Spec J. It starts fine but shuts down abruptly as soon as the start button is released. It doesn't stumble and die slow but shuts down immediately. This seems to be a common problem. It ran when I exercised it 2 weeks ago but it shut down on it's own. It has always done that once in a while. I went to start it recently and ran into this problem. Here is what I know.

Fuel supply is good. I tested it.

Plenty of oil.

Batteries good

No error codes.

No gnawed wires visible from the front. I removed the board and checked beneath too.

Air cleaner good.

Fiddling with the governor and choke make no difference.

I have been to the Flight Systems Inc site and checked their troubleshooting area but it states that this model (KY, Spec J) is not included because of a microcomputer. The problem is that it could be brushes inside, a bad sensor, the voltage regulator or something else. I'd like to narrow it down so I don't have to try drop the box in the driveway or replace the board without knowing if it's bad. Does anyone know where I can get testing info? It is interesting that the board is submerged in a block of some sort of plastic. Good idea since it is exposed to all sorts on nastiness but it makes it hard to examine.
One of my buddies had an almost exact same problem. It turned out to be the switch to start it at the generator. Contacts were bad. I took the switch apart and cleaned it up and it has worked fine ever since.
Happy Glamping.
__________________
Happy Glamping, Norman & Elna. 2008 Winnebago Adventurer 38J, W24, dozens of small thirsty ponies. Retired after 40 years wrenching on trucks! 2010 Ford Ranger toad with bicycles or KLR 650 in the back. Easy to spot an RVer, they always walk around with a screwdriver or wrench in one hand!
Unplanned Tourist is offline   Reply With Quote
Old 06-20-2017, 08:44 AM   #10
Senior Member
 
Kahoona's Avatar
 
National RV Owners Club
Freightliner Owners Club
Join Date: Jul 2015
Location: Conch Republic
Posts: 2,495
Quote:
Originally Posted by Unplanned View Post
One of my buddies had an almost exact same problem. It turned out to be the switch to start it at the generator. Contacts were bad. I took the switch apart and cleaned it up and it has worked fine ever since.
Happy Glamping.
Interesting. I have already ordered a replacement switch because the old one was decomposing and it should get here in a couple of days. It does it with the remote switch too though.
__________________
33' 2008 National Tropical on a Freightliner chassis.We tow a 2001 XJ (Cherokee) RVM#189
Kahoona is offline   Reply With Quote
Old 06-20-2017, 08:50 AM   #11
Senior Member
 
Monaco Owners Club
Join Date: Sep 2014
Posts: 4,569
Most "shuts off when I release the start button" problems have to do with the generator side of things. If AC is not being produced the genset will not stay running. Here's the service manual. I have two of the KY gensets and they are notorious for the rotors going bad (often from not being used)

Index of /~n0nas/manuals/onan
__________________
1996 Tioga Class C
2007 Monaco Diplomat 40 PDQ
TOAD 2012 Cadillac SRX 4
okcnewbie is offline   Reply With Quote
Old 06-20-2017, 11:56 AM   #12
Senior Member
 
Kahoona's Avatar
 
National RV Owners Club
Freightliner Owners Club
Join Date: Jul 2015
Location: Conch Republic
Posts: 2,495
Quote:
Originally Posted by okcnewbie View Post
Most "shuts off when I release the start button" problems have to do with the generator side of things. If AC is not being produced the genset will not stay running. Here's the service manual. I have two of the KY gensets and they are notorious for the rotors going bad (often from not being used)

Index of /~n0nas/manuals/onan
Wow! What a huge index of materials! Thanks. Is there a system that makes finding one manual easier. I see they have an 8 digit, hyphenated number at the start. Are these indeed anywhere by model? I don't sind my 4KY FA26100J but I could easily have missed it. I will keep looking later.

I have heard that the brushes or rings can be the problem. I want to check everything else first because just getting it out from under the RV looks difficult and dangerous without lifts and a forklift.
__________________
33' 2008 National Tropical on a Freightliner chassis.We tow a 2001 XJ (Cherokee) RVM#189
Kahoona is offline   Reply With Quote
Old 06-20-2017, 01:04 PM   #13
Senior Member
 
Monaco Owners Club
Join Date: Sep 2014
Posts: 4,569
I went over to smokstak.com ( great site for engine/gen repair help ) and it seems that your service manual might be 981-0530C. You should be able to Ctrl>F to find that manual on the link I sent previously.
If you go to smokstak you won't like what they have to say about the 4ky model and especially what the old timers think a used unit is worth.


With a second person they're pretty easy to get out.
The other 4ky service manual for pre K/J is 981-0503

Good luck.
__________________
1996 Tioga Class C
2007 Monaco Diplomat 40 PDQ
TOAD 2012 Cadillac SRX 4
okcnewbie is offline   Reply With Quote
Old 06-20-2017, 04:24 PM   #14
Senior Member
 
Kahoona's Avatar
 
National RV Owners Club
Freightliner Owners Club
Join Date: Jul 2015
Location: Conch Republic
Posts: 2,495
Quote:
Originally Posted by okcnewbie View Post
I went over to smokstak.com ( great site for engine/gen repair help ) and it seems that your service manual might be 981-0530C. You should be able to Ctrl>F to find that manual on the link I sent previously.
If you go to smokstak you won't like what they have to say about the 4ky model and especially what the old timers think a used unit is worth.


With a second person they're pretty easy to get out.
The other 4ky service manual for pre K/J is 981-0503

Good luck.
Got it. Didn't know about that Ctrl>F trick. Nice. I know how much we all love to hate them. I probably have a month's work in this one and it had quit running in 50 states so far but the alternative would be to put something else into a 2002 motorhome so I believe I will keep it running if I can. I dropped it down a foot to access the starter one time. I would have taken it out but raising the coach up enough to get it out from under would have been dangerous. I'll worry about that if I need to.
__________________
33' 2008 National Tropical on a Freightliner chassis.We tow a 2001 XJ (Cherokee) RVM#189
Kahoona is offline   Reply With Quote
Reply

Tags
onan



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Onan Marquis 5000 RV Genset Starter Stays on and won't run unless I hold the throttl creekside02 RV Systems & Appliances 2 04-04-2013 12:48 PM
2008 Onan 5.5KW Wont Start Unless You Choke Sandpirates2 MH-General Discussions & Problems 9 01-11-2012 03:35 PM
the key switch will not start the rv unless i press the auxillary button. why? fofdyfo RV Systems & Appliances 18 10-06-2011 11:50 AM
Generator Won't Start Unless I Run the Engine 69RoadRunner Newmar Owner's Forum 12 07-10-2008 05:28 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 05:07 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.