OK, TB 3 looks good, and things match up but unable to see several T windings labels but this is normal. You have at the load terminals with a load of "Not shown" with the digital AMP Probe, a little over a volt difference between L1 and L3 to Neutral. I'm going to ask to check something seemingly strange, and that is place the black lead on the Neutral and now use the red probe and measure AC voltage at the main Contactor at L1 and L3 input to the contactor from the S8 while running. The measurements should be the same as you previously had at the load terminals if everything is perfect which on an older gen it is not. Close is good, like within 1 Volt AC.
Once you have those readings now reading for AC Voltage, red lead on the input to K1 Main Contactor, black lead on the same phase at the output of the K1 for both L1 and L3. This will be a voltage drop across the contactor mating points inside. The AC Voltage should be about a volt or less. The higher this reading the more pitted the inside contact points are. The output of the K1 should be exactly as you read at the load terminals. Any difference indicates the filter circuits behind the load terminals are having issues. One wire on the TB3 is rubbing against the frame but this droops down like that after time. Just bend it up Slightly
Do me a favor, with the gen running, at load, set your DMM on HZ, measure L3 to neutral and adjust your speeder KNOB for 60.3 to 60.5 HZ using the DMM readings and then lock it back down. If different than the Freq gage, slightly calibrate the analog meter so they are very close and then you are more familiar with that gage. The gages are analog and measure more accurate around mid scale.
These gages are not very accurate on the best sets but you can get them close. Adjust your voltage adjust on the control panel so your DMM reads 120 at the load terminals and calibrate the AC Volt meter very slowly so it is closer to 240. Your 123VAC is actually good and a 125VAC puts less strain on the Voltage regulator, but no higher. With your load measure with your AMP Probe as you had shown in the initial entry. 25AMPs is about 50% of the 100% output of the gen of 52 AMPs per phase set on 120/240 at the S8. Your meter indicated 25% load but again it is on the left side of the gage too.
If you have an air compressor, put on a pair of safety glasses and blow out the dust. Just imagine this 4 inches thick as was the usual in Iraq, and a little less in Afghanistan. In Germany, things grew green hair on things and had rust. Ft Bragg seemed normal. Ft Lewis had sea rust and forget Hawaii. Your % load if everything else check out probably needs a tweak on the calibration button on the gage face, but here if you adjust it at 50% to be accurate with the AMP probe, it will be off at 100% as I never saw one reading correctly. Someplace between the 2 settings where you usually run the gen set is the best adjustment calibration setting.
If you down load the manuals from this site you will have the best we are allowed to provide for free, and I added things not in the manual I used with 57 other P&E LARs and Master Tech for 20 year Please remember, the gen is not a new item and has been abused by everyone since it was made. Like me at 70, I still get around , but not like 50 years ago or when I brought TQG gens into the ARMY in early 90s as a Warrant Officer and still in touch with the school house writing their courses.
