Duramax7man7 506 #1 Posted October 12, 2016 Have a 520h that I'm working on getting to full functionality. Noticed that there has been a loose black wire, it's long, coming from one of the posts on the ignition coil... Haven't had any issues of it not being connected since I got it. I checked for the condenser wire and it's connected. I've attached a photo of it. It's the long black wire connected to the post closest to the voltage regulator. It's not connected to anything and is long enough to stretch over to the battery compartment... Any ideas? Once again this is all new to me. So take it easy on me. ha ha. Share this post Link to post Share on other sites
N3PUY 1,031 #2 Posted October 12, 2016 My GUESS would be wire for the tach. Share this post Link to post Share on other sites
Ed Kennell 39,229 #3 Posted October 13, 2016 I thought the gray wire on the regulator was the tach signal. Black is normally just used for ground. Has the 9 pin engine connector been removed ? Share this post Link to post Share on other sites
cleat 6,729 #4 Posted October 13, 2016 Well, the black wire coming from the 9 pin is to ground the Hour meter. If that was connected to the plus side of the coil nothing would happen except the hour meter would not work. The only other thing I can think of is someone got power from there to run an accessory on the tractor at some point. 1 Share this post Link to post Share on other sites
Duramax7man7 506 #5 Posted October 13, 2016 15 hours ago, N3PUY said: My GUESS would be wire for the tach. The tach is working although not very well. It seems to not want to register very low... How many wires should I be looking at on the back of it? That might help me diagnose if it's hooked up properly. I'm not sure of the year of this 520h as the tag has been removed. But the Onan engine code is P220G-I/ 10955C and using the diagrams online for parts. Only the 1990 and 1991 520H used this engine code from Toro manufacturing. The last 6 alpha numeric digits are different in 1988-1989 and the codes completely change from 1992+ So this 520h should be a 90-91. IF that helps. 12 hours ago, Ed Kennell said: I thought the gray wire on the regulator was the tach signal. Black is normally just used for ground. Has the 9 pin engine connector been removed ? Looking at the photo I posted above, the two small wires on each post go to the Ignition control by the flywheel. The small post on the RHS of the coil goes to the condenser. The yellow wire goes up to the Molex and joins to two orange wires that go up behind the cluster panel. The only one left is the that black wire that is loose. I pulled the shroud, flywheel and stator yesterday (diagnosing charging problems in another thread) and when I pulled the coil wire all off, that black wire was just stripped and wrapped around the post and then nut was tightened. So it was definitely either after market of some type or reattached in a "Half-butt" type of way and then not connected. 2 hours ago, cleat said: Well, the black wire coming from the 9 pin is to ground the Hour meter. If that was connected to the plus side of the coil nothing would happen except the hour meter would not work. The only other thing I can think of is someone got power from there to run an accessory on the tractor at some point. The Black wire is only attached to the post on the left of the coil in that photo above. The other end is loose. It was stripped and just hanging around when I got it. I cut it and capped it for now. Everything seemed to be working fine with it there expect the Tach. It wouldn't go below 2500 rpms or so if memory serves me correctly. You may be right on the accessory... But why would they tap power form the coil? So that it would only have power when the ignition is on and not drain the battery I'm assuming. Share this post Link to post Share on other sites
Ed Kennell 39,229 #6 Posted October 13, 2016 There should be 3 wires on the tach. A pink wire to the ignition switch. A black wire to ground. A gray wire to the regulator. If you have charging and tach problems, look a problem with the regulator or its connectors. Have you found this manual? 1 Share this post Link to post Share on other sites
