Torino 14 #1 Posted January 3, 2014 Went to start my 520H today and it would not. It turns over and is getting gas but no spark. It was running fine before and has always started easy. Share this post Link to post Share on other sites
Martin 2,130 #2 Posted January 3, 2014 (edited) looking at the spark circuit for 1988 520 from the demystify manual i would go through each electrical component to eliminate. fuse, ignition switch, pto, seat switch ignition coil. easiest way for me is with a voltmeter and start from the fuse and work your way to the coil. could be just a connection, so move them about, even disconnect and clean the terminals if they need it. most of the time its a connection not making contact. if you get to the coil and trigger module and need to test them, the manuals have a quick test for those too. coil...... module..... i hope its just a connection or a fuse. the coil and module are an expensive fix...... Edited January 3, 2014 by Martin Share this post Link to post Share on other sites
Martin 2,130 #3 Posted January 3, 2014 these manuals are in the forum manuals section....... Share this post Link to post Share on other sites
leeave96 487 #4 Posted January 3, 2014 Went to start my 520H today and it would not. It turns over and is getting gas but no spark. It was running fine before and has always started easy. Just curious - how did you verify there was no spark. Good topic - I've got 4 of these 520H tractors and posts like this help educate me for whatever lies ahead when trouble shooting these engines. Thanks! Bill Share this post Link to post Share on other sites
cleat 4,996 #5 Posted January 3, 2014 One of my 520's had no spark. Ignition coil was bad. Bought a new one on ebay and now all is well. Cleat Share this post Link to post Share on other sites
Martin 2,130 #6 Posted January 4, 2014 of the 2 onans i got that weren't running, one was a bad coil, one was a bad ignition module. most of the intermittent problems with no spark or no start seem to be related to corrosion or bad fuse terminals or connectors, molex or others..... Share this post Link to post Share on other sites
Torino 14 #7 Posted January 4, 2014 Spark tester. You put one end on the plug and another in the wire and if it has spark it will light up. This is the first time I have had any problem with it for the last 3 years it has always started and ran great. Where is the ignition module? Share this post Link to post Share on other sites
TT-(Moderator) 1,128 #8 Posted January 4, 2014 The module is behind the flywheel. Have you checked for battery voltage at either small terminal of the ignition coil? {with the key in the run position} Share this post Link to post Share on other sites
Torino 14 #9 Posted January 5, 2014 No. I need to know where to start and where to go on from there. Check this first, then this etc. Share this post Link to post Share on other sites
TT-(Moderator) 1,128 #10 Posted January 5, 2014 If you check for battery voltage at the ignition coil and it isn't there, then you know it's something on the tractor. If there is power at the coil, then it's either the coil or the module. My 416H required wiggling of the ignition switch plug on occasion and I also had problems with the Molex connector between the tractor and engine harness. Hopefully it's just a loose or dirty connection on your tractor. Share this post Link to post Share on other sites
Torino 14 #11 Posted February 4, 2014 Forgot to report back. It ended up being one of the connections to the pto lever. Share this post Link to post Share on other sites
