Problem: I have a Generac 8.5kw generator model number 004692-0 and the starter doesn't disengage once engine is running.


First don't assume I know what I'm doing because I'm a newbie. I purchase this generator for $200 (cost of the new starter that wasn't root problem) from a neighbor after several attempt to have it diagnosed and repaired professionally. The original problem was sparks from flywheel case and shutdown with over-speed code. I believe the sparks came from the starter re-engaging while the engine was running. I'm told the teeth on the old starter where badly worn and thus was replaced. I understand over-speed code many times is caused by fuel problems but I need to address sparks first and starter not disengaging first. I pulled the flywheel and verified that nothing was rubbing on the backside which what the repair person wanted to do before being cut loose because the repair costs starting to outweigh value of the machine. The machine is about 5 years old but probably has less than 30 hours on it.

The current state is the generator will start and run (for about 15 seconds until it runs old of fuel. It runs out of fuel because I have it hooked to 1/2" line about 30 feet from regulator from a heater in workshop for testing/working out of the elements) but the starter doesn't disengage. How do I know the starter is good? First the starter is new. Second, I bench tested it and watched it engage and disengaged flywheel while mounted and cover was off and everything worked fine. I then reassembled everything and started the generator. It ran but didn't sound right. I could hear metal on metal but no sparks. I suspected it was starter not disengaging but not possible to inspect with cover on so I performed tests in service manual for relay and starter relay passed. So I then pulled wire 56 from the starter relay (12v input) once generator started and starter disengaged and engine ran smoothly and no metal on metal sound (until it ran out of fuel in about 15 seconds because of test fuel source and stalled with no light indicator on). While running I was able to confirm that 12v was still present on wire 56 which explains why starter didn't disengage. If you put wire 56 back on while running with 12v present it will produce sparks like the original problem as starter makes contact with moving flywheel. So the question is how and when will 12v on wire 56 suppose to be dropped?

I inspected wire 18 which comes from ignition coils and verified continuity from connector all the way back to pin 6 on the control board. Ditto for wire 56 to pin 5. Since engine ran I guessed magnetos/coils where ok. Also I was able to get a 3v reading on wire 18 at connector to ground with my multimeter. No idea if 3v is/was correct or accurate. Thus the control board was replaced but starter still doesn't disengage and 12v remains on wire 56 at the starter relay. Since the new control board didn't fix it I took it apart again and inspected the coils and wire harness again. I confirmed continuity of wires from primary coil to wire 18 connector. Diodes also seem to be good. I was able to measure 19k ohms resistance from both spark plug to ground (I.e. Secondary coil). The service manual says I should see 300k on primary coil but I see only .9 ohm on each coil (note measurement was taken with coil and plug wires disconnected). So is manual correct that 300ohms correct. Does this indicate a coil issue? Since both coils read identical resistance I have a hard time that thinking both have failed identically. A google search indicate that a less than 1 ohm is expected on the primay coil.

I suspect they signal/frequency being read by the control board is wrong because some issue with coil. Are there anymore test I can do to isolated the problem or test the coils before replacing them since they aren't cheap? I could see about borrowing a scope if I knew the voltage and rate that is excepted at the wire 18 connector while it is running. I'm on the right path or is there something else I could be missing like bad plugs, magnetos out of adjustment (but would have come from factory that way)?

Thanks in advance for any help or suggestions. Todd
8.5kW runs but starter doesn't disengage

Finally, I found the problem with this generator. Wire #4 is broken (completely) about 3" from where it attaches to the brushes. The question is what could cause it to break. Mouse? Or is there something else I need to check or do keep it from happening again?
What would cause wire #4 at brushes to break?

I found the reason why my 8.5kw is not generating any AC power. I found a broken wire #4 about 3" from where it connects
at the brushes. The wire is completly broken. What would cause the wire to break?
Generator worked for several years then just stopped working so it hasn't alway been broken.
I don't see any chew marks on it or burn marks. It just looks like it snapped. Any ideas what
could cause a break? What else should I check before repairing wire and putting it back together?
How much is a new gen?
It's possible the wire broke from vibration and fatique. Check if there's someplace close where the wires could be tied off to prevent them vibrating.