Onan 5500 Genrator won't start

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bigbryz

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Mar 17, 2014
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After waking up my RV from winter, had some battery/grounding issues, which were resolved. Before all that, the generator started up just fine.  during the durarion of fixing the starting problem, the generator would not start. I thought it was related , but, after fixing the battery/starting issue, the generator still will not start.. I disconnected the fuel line, and see it's pumping fuel fine.
pulled sparkk plug, and grounded it while trying to start, and see no spark at plug. So, question is, why no spark? Fuse is good. Replaced spark plug on outboard side.
Cluse?
 
bigbryz said:
After waking up my RV from winter, had some battery/grounding issues, which were resolved. Before all that, the generator started up just fine.  during the durarion of fixing the starting problem, the generator would not start. I thought it was related , but, after fixing the battery/starting issue, the generator still will not start.. I disconnected the fuel line, and see it's pumping fuel fine.
pulled sparkk plug, and grounded it while trying to start, and see no spark at plug. So, question is, why no spark? Fuse is good. Replaced spark plug on outboard side.
Cluse?
Click to expand...
the CDI ( capacitive discharge ignition)box is bad.its like s distributer and coil all in one. same as a weed eater or a lawnmower system uses
 
whats it look like, wheres it located?
Wonder how it could go bad all of a sudden like that.???
 
bigbryz said:
whats it look like, wheres it located?
Wonder how it could go bad all of a sudden like that.???
Click to expand...
u need to get a repair manual+parts list. it could be the control board also. I am not sure where it is on that gen set
they will go bad just like that.
 
Lou Schneider said:
Everything on the Onan engine is controlled through the generator's controller board.

Flight Systems makes replacement controller boards for Onan commercial and RV generators and they have an excellent RV generator troubleshooting guide.  Follow the test procedures at the front of the guide and you'll quickly isolate the problem.
Click to expand...

yes but the ignition system could (cdi) be the culprit as much as the board could be  I guess one needs to know the vintage as the late model ones are pretty much all electronic. 
it,s oil pressure switch causes control board to keep sending 12 volts to the ignition  so  bad oil pressure switch? another possibility
 
That's covered in Step 2 of the Troubleshooting procedure, where you jumper a couple of pins on the circuit board interface to send battery voltage directly to the CDI.  On a non-CDI generator you temporarily lift the oil pressure sensor lead.  If the engine then starts, it's the control board or one of it's logic inputs holding it off, which are tested in subsequent steps.  If not, the CDI or oil pressure switch is defective.
 
Humm. I think this is a good point to say something..

Operating on the theory that "Forewarned is forearmed" I am downloading the Trouble Shooting guide. Lou linked to,, Thank you Lou.

And operating on the theory that the emergency you are prepared for will never happen.  this means I should never need it :)

(Too bad that theory is flawed).  But thanks, and I hope the 2nd theory works.
 
I am adept at troubleshooting electrical problems, just need to know where the control board and CDI  are located, as I am fairly new to RV's. This is a 1986 Minnie-Winnie. I have most of the manuals, but, don't see the physical location of these devices.
thanks,
 
bigbryz said:
I am adept at troubleshooting electrical problems, just need to know where the control board and CDI  are located, as I am fairly new to RV's. This is a 1986 Minnie-Winnie. I have most of the manuals, but, don't see the physical location of these devices.
thanks,
Click to expand...
cant say off hand but must be pretty obvious as their definitely attached to the gen set.if you take a few minutes and look things over you will discover them for sure
 
Lou, thanks also from me for the troubleshooting guide link.  Despite replacing the carburettor last season, I'm continuing to have some issues.

Dougie.
 
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