The way to understand a wiring diagram is to understand all the symbols. If you do not know what the symbols mean, then you will not know how to repair the coil on this generator. The next key is to know how to read the diagrams.
Coil diagrams for the Onan generators can be found on the internet. They may not be found in the different owner’s manuals for the many generator models. But you may be able to find them in repair shops or by contacting the company directly.
To learn more about Onan coils and view their wiring diagrams, just continue to read our article. It has the information and the diagrams for you to see. If you are a DIY person, then these diagrams should come in handy and help you make your repairs.
This diagram is represented as being for the Onan generator coil wiring diagram at the image results page and at least one other website. It should provide you with all the key details you need to make your repairs.
The same could be said for this wiring diagram. This image is for the Onan P-series of generators and it may not be useful for other models. It has been said that most owners do not have a lot of issues with the coil on these generators.
The people making that statement claim that it is the points that cause the most problems. However, there are those people who disagree with them. Your coil may or may not cause you trouble.
But when you need to work on the coil and use the wiring diagrams above, the second biggest key is essential here. Since most diagrams show the current flow between the different components, to read a diagram correctly, you start at the left side and follow the current flow to the right side.
Just make sure to know the biggest key to understanding a wiring diagram. Those symbols will help you a lot in identifying key connection points. The color of the wires will help in this identification as well.
The process seems to be very simple and straight forward. The first step is to disconnect both the positive and negative wires attached to the coil. The second step is to attach a jumper wire from the battery's positive post to the coil’s positive post.
The third step will be to attach another jumper wire to a good ground location. Then tap the ground wire to the negative post on the coil. The spark plug should spark if all is well.
If there is no spark then a wire is bad and you should replace both wires to be sure. You can also check for continuity by using either a volt meter or a multimeter.
With the multimeter, you touch the probes to the two terminals and then record the reading you get. Then compare those readings with the recommended readings. If these two figures are not the same, then you have a bad coil.
Other tests are available and they rely on if you get a spark at the plug or not. Unfortunately, the lack of a spark indicates several different sources other than just the coil.
Those sources include a crank sensor, ignition module, a damaged wire in the primary circuit, or a malfunctioning ECM/PCM. If you are not getting a spark but the coil has power, then it may be up to the technician to handle the diagnosis and repair.
You are in luck as these parts seem to be available just about anywhere generators are sold and repaired. They may also be found in those repair shops that work on small engines.
Amazon has a very large selection of coils and that is due to the many generator models that Onan builds. Or you can contact Cummins directly and see what kits they have on sale.
One kit costs $153 while the Amazon selection is well under $50 just for the coils alone. To make your purchase, make sure to have your parts or model number handy. Those numbers are always needed when it comes to buying any part.
1. Onan used to be an independent company but it is now owned by Cummins. To find a part you may have to include the Cummins name. These parts can be listed as Cummins Onan or Cummins part # Onan.
2. Make sure you know your generator’s fault codes. Or at least have them handy so you do not spend time looking for them. The codes will cut down your search time and help make the repair go faster.
3. Know what parts are on your generator. Some models do not come with an oil filter. This makes it essential that you never use old oil in those models.
4. Know the power capacity of your generator. While it may seem like you can plug anything you want not your electrical system when the generator is running, it is not so. All generators have limits so monitor your electrical use carefully to avoid issues.
5. USDA Forest Service Approved. This is a label you may see on some Onan generators. What it means is that you can run your generator inside the different national parks without any problem
6. National Park Service noise level approved- most Onan generators meet this requirement. It means that your generator’s when approved, noise level is 60 decibels or less.
In many cases, your repair of the coil usually means replacement. You can pick up good Onan coils at many locations that are near you. Then follow the wire diagrams to connect the new coil correctly.
The last thing you want is to create an electrical problem while trying to solve an electrical ignition problem.