dwcphoto 7 #1 Posted March 24, 2013 Hi Guys, I put a new voltage regulator on my WH 518 Onan last summer. While the tractor does not stop running due to lack of charge like it did before, the volt meter on the dash is not showing a charge. A friend asked if I polarized the system when I put the new regulator in and I had not. Can anyone explain this to me? I don't know if it was in the directions/instructions when I got the new regulator or not. Thank you, david Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #2 Posted March 24, 2013 The older mechanical voltage regulators sometimes required polarization but not the small electronic versions. What is your tractor's long model and serial number? Will look for the appropriate wiring diagram so you can figure it out. Garry Share this post Link to post Share on other sites
dwcphoto 7 #3 Posted March 24, 2013 Thanks for your response. My 518H is an Onan Performer 18XSL. The ID # is 31180E01 10112. Thank you! david Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #4 Posted March 24, 2013 Here is the tractor operator manual Here are the detailed wiring diagrams Your model number is written like this 31-18OE01 O=Onan engine E=Eaton hydro Last 2 digits are numbers zero one. Garry Share this post Link to post Share on other sites
Cable 180 #5 Posted March 25, 2013 Volt meters on our tractors are not known for their accuracy. The way I check for charging: 1.) is to turn on the ignition switch to the first position and note the voltage reading displayed, then 2.) start the engine and after warm up again note the voltmeters displayed reading. Generally it will be 2 or more volts higher. If you have a good portable digital test meter you can do the same thing with the meter on the battery terminals. Corrosion at the regulators center terminal, at the 9 pin connector pin #7, and at the fuse can cause poor charging performance. Most of my experience is on the 520 tractors with the P220 Onan engine. I find that a voltage drop of more than 150 mv from the positive battery terminal to the regulator center terminal is indicative of corrsion. Share this post Link to post Share on other sites
dwcphoto 7 #6 Posted March 25, 2013 Thank you, guys for your help. I'll check all this out and try to see what's really going on with the volt meter. There certainly is a chance of some corrosion. Much appreciated. dwc Share this post Link to post Share on other sites
dwcphoto 7 #7 Posted March 28, 2013 Hi, I got a few minutes to check the voltage on the tractor. Before I start it, I get about 11 volts with my analog meter. When it's running I get about 10. Definitely a bit less. dwc Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #8 Posted March 29, 2013 The Onan service manual describes the test proceedure Garry Share this post Link to post Share on other sites
dwcphoto 7 #9 Posted April 2, 2013 Hi Guys, Thanks again for your help. As it turned out, it was a bad battery. The other one held a charge, but dropped under a load. With a new battery it started right up without assistance. I will check the other things as I get time, too. Thanks, dwc Share this post Link to post Share on other sites
