Forum Discussion

maillemaker's avatar
maillemaker
Explorer
Apr 08, 2018

I believe my coil is bad on my Onan 4BGE generator

Hi all:

Generator is Onan 4BGEFA26101A

Which I take to be a 4BGE, Spec A, Onan Generator.

The generator cranks, but will not start.

I used a spark tester light, which goes between the spark plug and the boot, to determine that there is no spark to the outward-facing spark plug. I did not bother to check the inward-facing plug once I determined there was no spark on the outward plug. I tested the plug light on the RV engine itself and the light works.

I removed the coil from the genset, and performed the following resistance tests on the primary and secondary coils:



It looks like the primary coil is good, measuring 3.6 Ohms. It should measure between 3.87 and 4.73 Ohms. It is a little under but this is probably OK.



I believe the secondary coil is bad, measuring only 17.4 K Ohms. It should measure between 34.0 and 41.6 K Ohms. This is way out of spec, and indicates a shorted coil according to the manual.



Does everyone agree I'm reading my Ohm meter correctly? I'm not an electrical person.

The coil is marked 166-0761:




This coil with built-in mounting brackets does not appear to be available anymore. I see replacements, with separate bracket, available on ebay.

Some are listed as HE166-0761. What is the difference between HE166-0671 and 166-0671?

Here is a non-HE one for $86:

https://www.ebay.com/itm/New-Ignition-Coil-For-Onan-Generator-Welder-Factory-541-0522-Replaces-166-0761/173128934985

And here is an HE one for $60:

https://www.ebay.com/itm/Replaces-Onan-Ignition-Coil-P-Model-541-0522-166-0820-HE166-0761-HE541-0522/173225446794

Thanks,
Steve
  • Read up in the service manual about the control module arms they can break off. Which manual are you looking at so I can look it up. Look in 965-0528 page 6-10 at the ignition module.
  • possible its a fuse?


    The only fuse I am aware of is the one on the control board. It is fine.

    I believe the control board decides whether or not to allow the generator to start by controlling the ignition and fuel circuits. Next weekend I will follow the service manual debug instructions for checking the control board and voltage regulator.

    Steve
  • OK, the coil is not bad. Now that I know I have a Spec G genset, when I read the section for Spec G gensets it says:



    So, my primary coil is just a hair low, and probably fine, and my secondary coil is also just barely a hair low. So my coil is probably within specs for a Spec G genset.

    So now I have to figure out why I'm not getting any spark.

    Steve
  • Looked in the parts manual and it shows 166-0772 it is available.


    Do you have a link to a source?

    Also, I just discovered that the genset is actually a 4BGEF826101G. This is from the tag on the genset, which differs from the RV owner's manual summary page!

    This is good news, as it means that I have electronic rather than points-based ignition.

    Steve

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,211 PostsLatest Activity: Mar 08, 2025