I have three of the Nippondenso Kohler starters which had solenoids that got weak, so I ordered some off Ebay. I cleaned the starters and put the new solenoids on. The starters all work good when bench tested using a battery charger as the 12V source. When I put them onto older walkers the solenoids dont work consistently. Sometimes when you turn the key, the solenoid will just click. Does anyone have an idea of why they work on bench and not in mowers. I have tried connecting a wire directly from the battery to the 12V terminal usually connected to the ignition circuit and no change. I was thinking that maybe the grounding through the frame was not as good in the older units because of corrosion or something else over time. I have not yet tried using a grounding wire directly from the battery. Does anyone else have any ideas? Thanks for any help. I have replaced each of these three starters with new starters and they work fine, so that is something else that baffles me.