Onan Generator clicks but will not start

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HueyPilotVN

Well-known member
Joined
Jun 5, 2012
Posts
3,275
Location
Lake Havasu City, AZ
I have an Onan HDKAK 8 KW Diesel Generator that just clicks but will not start.
First of all I did do a search and also read the troubleshooting section of the Onan Manual.
The suggested problem is low voltage from the starting battery.
I have alread done several things. 
I tried starting the main engine and also using the boost switch to tie the batteries together.  No difference.
I checked the voltage at the terminals on the back bottom of the generator and read 13.8 volts.
I had hoped that it was a loose connection in the cable between the batteries and the generator.
I was not able to check the voltage while cranking because I am alone.  The cable connections seem to be tight.
Any ideas would be welcome.
 
I just thought of something else to try.  I am going to use jumper cables to see if it will start from the toad battery.  Problem is that I am too old to be crawling around under the rig.  Will post if it works or not.
 
I just tried to use another voltage source at the cable connection on the rear of the generator.  I have the same result.  I think I used up all the easy solutions.  The problem must be within the generator itself.  I am in Solano Beach, California, any recommendations for a good Onan shop?
 
I?m sure others will offer ideas, my thought is it?s perhaps the starter relay not passing the juice to the starter. Also I?m a stickler for all clean wire connections, everywhere. Perhaps you can bypass the relay and jump directly to the heavy cable on the starter? That might indicate where the problem might be.
 
Perhaps something else to try. We have an Onan diesel generator, also, that would not start. Finally got it to start by "priming" for a long time - we had a tiny air leak in the fuel line and the fuel would drain from the lines when sitting. On ours, you prime by pushing the rocker switch up for a couple minutes. Good luck.
 
I gather it doesn't try to crank at all? Just keeps a steady clicking (which is an artificial sound it makes to show the glow lug is in the heating cycle)? If the clicking goes on indefinitely, it probably means the glow plug never gets hot. Low voltage would be one cause of that, but not the only possibility. If the clicking stops but it still doesn't crank, there should be an error code displayed (blinking light on the start switch).
 
Thanks for the responses.  At this point I do think that the problem is internal to the generator and not a low voltage issue.  I called and got an appointment with RV Specialist in San Diego to take it in next week.  They suggested that it might be a sticking contact in the generator.  I will post the results after the appointment.
 
Check this as a possible solution before buying anything or paying for service.

http://www.rvforum.net/SMF_forum/index.php/topic,57527.msg529844.html#msg529844

Try to turn the flywheel by hand.  This will tell you if the problem is mechanical or electrical.  My guess is starter jammed on the flywheel.  Was my problem and another forum member that I helped.
 
Bob,

Thanks for the input.  I am going to let the mechanic check it out.  I had open heart surgery ten years ago and for some reason I cannot lay flat on my back under the coach withoug getting dizzy.  I will pass along to him your experience.
 
I had a new fellow that pulled into the RV Park pull the starter this morning.  It came out thru the service door underneath the generator.  The starter spins when hooked up to a battery with jumper cables but the bendix spring does not engage to move the gear forward.  I went online and ordered one from Amazon for $138.00.  Will post after we replace it but I do think that was the problem.  I did have a code 36 when I retrieved the error code.
 
HueyPilotVN said:
I had a new fellow that pulled into the RV Park pull the starter this morning.  It came out thru the service door underneath the generator.  The starter spins when hooked up to a battery with jumper cables but the bendix spring does not engage to move the gear forward.  I went online and ordered one from Amazon for $138.00.  Will post after we replace it but I do think that was the problem.  I did have a code 36 when I retrieved the error code.
While the starter is out, it would be super easy (and wise) to turn the flywheel with a screw driver (as someone else suggested). You want to be sure that the crank will turn before you put the starter back in.

It probably will turn freely, it's just best to rule out a hydraulic lock up or something broken while it is easy to do.
 
And you are positive that you have adequate fuel in tank so it's not as simple as the low fuel sensor preventing it ?
 
Update:  Today we installed the new starter.  We first checked to see that the flywheel did turn.  It did.  We reinstalled the fuel filter, fuel lines and electrical connections.  We got it to crank after holding the swith in the prime position.  It would not start.  We disconnected the fuel supply line and it did not seem to have any fuel in it.  I went and bought a 5 gallon diesel can and 6 feet of 3/8 inner dia fuel hose.  By using the can and running the fuel line directly to the generator. I was able to prime it, start it and it ran fine.  The problem now is definetly not the generator.  I cannot get the generator to run from the fuel line that is coming from the main common tank.  The tank is 3/4 full of diesel and the main diesel engine runs fine with no problem.  I am going to try replacing the fuel line from the tank to the generator tomorrow.  It is very hard to get to and might require dropping the main tank.  Another thought is maybe there is Algae in the tank blocking the pickup, although I would think that it would also have an effect on the main engine.

Another thing that I discovered is that when the fuel pump is priming or pumping fuel the clicking noise goes away, when it is pumping air then the clicking is loud.  Also when you hit the start switch it may click for about 10 seconds before it actually cranks.  I may not have been holding it down long enough when I first diagnosed it with a bad starter.  The starter may have been good all along.
 
There may be a plugged fuel filter in the line. If not, blow air through the line by mouth (use a clean extension hose). If you can't blow air into the tank, there is an obstruction. I'm not sure that I would used compressed air but if you do, be careful not to break anything. There may be a strainer in the tank and you may not want to blow it off.

If you can blow into the hose and it passes freely, you either have a leak in the hose (or hose is disconnected) and the pump is sucking air...... or the pick-up tube inside the tank fell off....... or the fuel gauge is inaccurate and you are low on fuel.
 
Thanks for the reply.  I neglected to say that we did use an airline to blow some air through both the supply and return lines.  We could hear bubbles in the tank and we did get a return rush of fuel.  I got it to start briefly and it quit.  Using air through the return line also briefly produced fuel.  I do think I either have an air leak in the line or a clogged pickup screen.  I do not think that there is a filter in the supply line, but I cannot see most of the fuel line as it goes above the visable area.  The fuel filter on the generator is new, but that was eliminated as a problem when the generator ran fine from a portable fuel can.  Unfortunately the large fuel tank in center of the coach and held in place on a frame supported on threaded rods.  With over 100 gallons of fuel it must weigh close to 800 pounds.
 
HueyPilotVN said:
Thanks for the reply.  I neglected to say that we did use an airline to blow some air through both the supply and return lines.  We could hear bubbles in the tank and we did get a return rush of fuel.  I got it to start briefly and it quit.  Using air through the return line also briefly produced fuel.  I do think I either have an air leak in the line or a clogged pickup screen.  I do not think that there is a filter in the supply line, but I cannot see most of the fuel line as it goes above the visable area.  The fuel filter on the generator is new, but that was eliminated as a problem when the generator ran fine from a portable fuel can.  Unfortunately the large fuel tank in center of the coach and held in place on a frame supported on threaded rods.  With over 100 gallons of fuel it must weigh close to 800 pounds.
That spells "ROAD TRIP!!!!!!!!"....... Put some biocide in the tank. If it's algae, it will turn the algae to burnable fuel.
 
Biobor JF, available at West Marine and some other places. Very popular with the diesel yacht crowd.

But I do not believe that any diesel biocide will convert algae to burnable fuel. It just kills the algae, which ends up being pasted on on an intake screen or in a filter. I also feel there is very little chance that you have algae affecting the generator but not the main engine.
 
All I can say is that I saw a demo on this stuff one time. They put a drop of it into some heavily contaminated fuel and it turned from a black slimy substance to crystal clear fuel which they then put into a small diesel engine and ran it. They claimed that the algae was killed and converted to a clear "Combustible" matter that would pass through a 2 micron filer easily.

The fuel tank on my yacht was badly contaminated and I was changing fuel filers every 50 hrs because the tank was contaminated with algae. The boat yard in Annapolis MD wanted $1100 to cut a big hole in the top of the tank, install a clean-out port and clean the tank.

I tried putting a strong dose of this stuff in 1 of my 2, 60G tanks and my filter clogging problems went away. Then I treated the other tank. I put that stuff in my fuel after that and had no more issues for the next 8 years (until I sold the boat in 2000).
http://www.biobor.com/fuel-additives-products-biobor-md-index.php
"Sludge dispersants break up and dissolve fuel sediment sludge into small enough particles that will pass harmlessly through filters and injectors"
 
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