ebinmaine 63,119 #1 Posted July 20, 2021 We have a techie 10 that runs well but has the VR wires disconnected. Off the engine there are two yellow wires and one green. Both yellow just hang. One of them was cut short by a PO and a fuse added. That's now fallen apart so I'll reattach as necessary. I believe once running I can simply read the output across those two AC wires to test the alternator output. I understand there are some engines that will have ignition/charging system damage if the VR goes bad. How does that happen and what if it's not even in the system? Can it run long term without those yellow wires even being connected ? Is there a way to test the VR? Is there a way to isolate the circuits to prevent damage if a component goes bad? Or install a guage/light or both to keep checks? I'd like to get this engine/tractor back to using the charging system at some point... Without causing damage. Thanks folks! Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,496 #2 Posted July 20, 2021 8 hours ago, ebinmaine said: I understand there are some engines that will have ignition/charging system damage if the VR goes bad. How does that happen and what if it's not even in the system? I think the problem is with other electrical equipment getting a surge or high AC voltage. Have learned that one of the AC leads is connected to the DC+ inside the regulator. Depending how the VR fails it may cause damage. Can it run long term without those yellow wires even being connected ? Yes as long as they can not short together or to ground. Is there a way to test the VR? No One test not advertised is to compare the voltage across the battery posts to the VR DC+ voltage with the engine NOT running - should be the same reading. Some models require the key to be in the RUN position to get voltage at the regulator. This confirms the charging current has a path to the battery. Also a VR requires battery voltage to turn it on so to speak so it can regulate the charge current. Is there a way to isolate the circuits to prevent damage if a component goes bad? Or install a guage/light or both to keep checks? Some models with breakerless or magneto ignition have a diode in the ignition wire to prevent stray spikes from destroying the ignition electronics. What causes the spikes I don't know. Could be the AC if the regulator fails or the ignition switch if it fails. Any case cheap insurance I think. A voltmeter is the best to monitor the complete charging system. The Kohler M-Series service manual illustrates the diode in the coil ignition wire. I'd like to get this engine/tractor back to using the charging system at some point... Without causing damage. Thanks folks! Garry 1 1 Share this post Link to post Share on other sites
