Diffculty starting Onan 2500 genset

Are you using the "prime" function....every time you start it ?

Have you looked at the external linkages on the carb to see if they need cleaning ?

How long since you ran a dose of a good carb cleaner though with the gas ??

No, starting fluid won't damage anything.....IF you leave the air cleaner ON and use the ether sparingly. In a pinch, propane works too.

And finally, this can sometimes be a symptom of an impending problem with the 12 V battery system.

Mine has always been reliable. You might try finding all of the normal fixes like cleaning the intake tube of insects, for instance.

If it is difficult after sitting, you may have a propane leak requiring the line to reprime. Did you do anything with the regulator or line pressure? Mine was always reliable even after 275 hrs run time in 4.5 years.

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Does the non-starting issue occur after you have shut off the propane tank for awhile? If so, it's probably just leaking propane a bit and needs to re-prime in order to start. I'd try a good cleaning of the intake and changing the plugs before resorting to starting fluid on a regular basis.

There are so many things it could be... A very long process of elimination but you need to start somewhere. First, start from the beginning.. at the tank. Look at the end of the fuel line for any obstruction is it getting fuel to the regulator? Next if the line has any dip in it, it can collect junk and the oily stinky stuff that may be blocking the hose to the regulator. It is like tar, one day clear one day plugged. Remove the hose to the regulator and make sure it is clear. Next the regulator itself. How old is it? Is it an auto switch? Remove the line on the out side that goes to the generator, is it getting fuel through the regulator? Trace the line to the Generator. Remove the line from the generator and while you have it disconnected from the regulator and the generator, blow compressed air through it and make sure it is clear. Now for the generator itself. How old is it and what model is it? When did you replace the air filter if ever? Did you check the filter cover? It has to be properly seated or it will not run. Does it have a breather hose that is just inside the cover? Check if it is plugged with insects. If it does have the hose, put a screened filter on it. Check the oil level? Oil cut off switch could be an issue. Have you changed the plug? Do it just because. Check the plug wire, it can ground out if rubbing on the case, it is a very tight fit. This is just a start. There are so many different ones. A model number would help a lot as then we would know at least what and where to start if it is even the generator at all. Again start with the lines and regulator first...regulators are cheap, replace it regardless, they can fail at anytime.

Bedlam wrote:
If it is difficult after sitting, you may have a propane leak requiring the line to reprime.

Where did he say it was propane operated ??

The choke linkage would sometimes bind on ours. On start, the choke would close and stay closed until the linkage slipped back to open the choke.

Thanks for the info... will start the checklist.... be back in a few days.....Dave

I don't know how old it is but it does have a 3yr warranty on it. I just went through the same thing and Cummings/Onen had to put a new carb on a 2015 Gen with 12.2hours on it