Hi there! This video led me down the right path and I was able to fix my 10kw Generac Guardian's overcrank issue. I watched how your stepper motor switch behaved when you were fiddling with it... it would spring back into the original position each time you moved your finger. I noticed that when I did the same with mine it didnt spring back, almost seemed like it would stick to wherever I moved it to. It turns out that the switch pin that fits in the slot on the curved flat piece was being obstructed from free movement by some black corrosion on that flat piece. I sprayed a bit of PB Blaster and carefully cleaned the gunk off the flat curved slotted piece with some fine steel wool. The whole component now seems to move freer, and when I hit the manual start it fired right up. I watched it when the unit was running and could see how it makes subtle adjustments, and being stuck must have been causing it to run improperly even when I could actually get it to start. The other thing I noticed (unfortunately) is that there is an occasional tiny puff of gray that pops out of where the manifold pipe bolts into the front part of the assembly... There are two hex bolts where it attaches, and the puff of smoke seems to be popping out of one of the bolts. It's not constant, very intermittent. I also noticed that the bottom of my unit's box has a fine covering of what appears to be an oil mist. I checked my oil level and its normal, so not sure what that is that Im seeing. I made a video of it happening and may post it here to get some suggestions.
The over-crank message is about the control sending a signal (several times) and the unit failing to start. A gas issue is probably the most common, but a poor connection to the starter or a failed starter can also cause this, along with a failed stepper motor (throttle control) mentioned in this video. BTW, it this happens shortly after a battery replacement, it's likely that whoever installed the battery fumble-fingered it into place and yanked the harness of the stepper motor out of the control board, which is directly above the battery but hidden in the dark.
I moved the stepper motor and mine seemed to not move as freely as it should, but I did follow these steps and I did get it to start in manual but still says inspect battery. Question; can I lube that stepper motor with something? I noticed some slight rust on it but I didn’t know if I could lube it for fear of the lube catching fire being right by hot components.
