gcole 36 #1 Posted January 6, 2013 Hi guys I was wondering if you could help me with some wiring on my 18 hp onan on my new 312 puller ( pics to come when I get the camera) I was wondering were the wire from down in the engine shroud goes to the A terminal on the ignition switch and if the wire on what looks like the regulator on top of the rear cylinder engine shroud goes to the R terminal on the ignition switch and if not could you guys point me in the right direction Thanks in advance Share this post Link to post Share on other sites
gcole 36 #2 Posted January 8, 2013 Anybody have a simple wiring diagram for this engine?? Thanks in advance Share this post Link to post Share on other sites
Save Old Iron 1,571 #3 Posted January 8, 2013 Graham, sorry, I did not see this post until tonight. Concerning the "engine shroud wire" - do you know where it is attached on the engine ? maybe a picture of the end of the wire where it attaches to the engine? It could lead to the cylinder head temp sensor, oil sensor, tach output, etc. No way to tell without visual ID. Wiring colors can be useless on the Onan block. I have seen some with all black wires leading from the block to the 9 pin connector. The center "B+" terminal of the regulator (on the shroud) can go to either the "R" of the "A" terminal. I believe the 520H WH tractors have it to the "A" terminal. Pictures would be best, as guessing with Onan electrical parts can become expensive very quickly. Also, be very sure you are using the proper ignition switch. An ignition switch intended for a magneto based system will cause headaches - expensive headaches. Check to see if the ignition switch has "G" or "M" terminals. This would be the INCORRECT switch and can cause difficulties. A wiring diagram can be had in the MANUALS section - look for and download the DEMYSTIFICATION GUIDE. Check out the 520H section. Share this post Link to post Share on other sites
