Hi all. I bought a B7510 (older metal hood version) that had been sitting for a few years. Owner has recently passed, so I can't really get any history other than "he was running it and it broke down". After changing fluids and replacing the battery I found I had a crank/no start situation. A little more checking narrowed it down to the Engine Stop Solenoid not activating. On this tractor, the solenoid must be energized to run - opposite of many where the solenoid energizes to shut down the injectors. I ordered an aftermarket solenoid off Amazon and the tractor fired right up. I used it for a week intermittently with no issues, then it suddenly died and I thought I could smell electrical. Engine stop solenoid was incredibly hot, the fuse heading to it was blown, and it smelled burnt. I ordered another one and went back to troubleshooting. The Solenoid has 2 wires coming in - one for the pull circuit and one for the hold circuit. My understanding was that hold should be always on when the key is on, and that pull should only activate when the key is on crank. I found that the pull circuit was always energized when the key was on. I then replaced the relay under the dash that powers the solenoid, but nothing changed. Things seemed to point to the OPC, but further testing seems to cast doubt on that. My testing shows that the relay under the dash applies power to BOTH circuits simultaneously. The wiring diagram in the WSM seems to confirm this, as it shows the wires for both sides tied together. I can't see where any wiring has been modified from factory.
At this point I'm leaning to one of 2 possible explanations - either the OPC does some sort of magic I don't understand (or the wiring diagram in the WSM is wrong) - in which case the pull circuit should only be engaged when the key is in crank, and I need a new WSM....OR...the factory solenoid has an internal control that cuts power to the pull circuit when the solenoid is activated, and both circuits should be hot anytime the key is on, in which case I just need to order a factory solenoid. Can anyone confirm whether both circuits are actually supposed to be tied together and the solenoid actually handles cutting out the pull circuit itself? Or has anyone experienced this to point me in the right direction? Appreciate any help!
At this point I'm leaning to one of 2 possible explanations - either the OPC does some sort of magic I don't understand (or the wiring diagram in the WSM is wrong) - in which case the pull circuit should only be engaged when the key is in crank, and I need a new WSM....OR...the factory solenoid has an internal control that cuts power to the pull circuit when the solenoid is activated, and both circuits should be hot anytime the key is on, in which case I just need to order a factory solenoid. Can anyone confirm whether both circuits are actually supposed to be tied together and the solenoid actually handles cutting out the pull circuit itself? Or has anyone experienced this to point me in the right direction? Appreciate any help!
