AlpacaFarmer 0 #1 Posted June 1, 2015 I bought a 520-H this spring and it won't start. It did start once and ran good for about a minute and died, it hasn't started since. After tinkering with it I found it has no spark. Could it be the ECM or coil and how would I test them? Share this post Link to post Share on other sites
rmaynard 15,710 #2 Posted June 1, 2015 Could be either one, but first, what is the year of your 520-H. Here is a wiring diagram of the spark circuit for the 1991-1997 models. There are a couple of things to check first. Check the 25 amp fuse, and make sure that the seat switch is being activated, the PTO is disengaged, and the motion control lever is in neutral. By looking at the diagrams below, any one of those plus a bad ignition switch, switching relay, kill relay, trigger module or coil could be at fault.But always check the obvious stuff first. 1 Share this post Link to post Share on other sites
squonk 41,604 #3 Posted June 1, 2015 Not only check that fuse, check the fuse holder. I've had more than 1 tractor with a good fuse but the holder was corroded, burnt ect. causing a no start or intermittent connection. 1 Share this post Link to post Share on other sites
AlpacaFarmer 0 #4 Posted June 1, 2015 How do I find out what year it is? Share this post Link to post Share on other sites
ericj 1,578 #5 Posted June 2, 2015 down load the onan service manual on here and it will walk you through step by step how to trouble shoot your onan and make it purr again like new loleric j Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,122 #6 Posted June 3, 2015 (edited) How do I find out what year it is? Should be a decal on the rear fender pan under the left side of the seat. Model number and serial number should be on it.Failing that post all the numbers off the engine's data decal. Sometimes the tractor model can be determined from them.Hood side decal maroon or black? From 1990 on they are black.Garry Edited June 3, 2015 by gwest_ca Share this post Link to post Share on other sites
doc724 925 #7 Posted June 4, 2015 Here is my 2 cents on this based on my limited experience with my 416H (which I just got 2 weeks ago). I have use it 3 times and it starts and runs great. Then yesterday, as I was blowing off the grass after cutting and it was sitting in the driveway it just died. So I got back on the seat, turned the key and nothing, not even a click. I got off, wiggled the seat safety switch, got back on, still nothing. Got off, pushed all the fuses down, got back on and voila, started right up. My conclusion is that I agree with Squonk, the fuse holder terminals are suspect. I have another 416H and it does not start at all, yet I know it runs as I drove it before I bought it. So I bought a new fuse holder, new terminals, a new molex connector kit and a nice wire crimper. Now to find time to work on it! Oh, and now that I know that my working 416H is a few gremlins, I need to delve into that as well. Share this post Link to post Share on other sites
shallowwatersailor 3,213 #8 Posted June 5, 2015 (edited) My '89 520-H started in the winter after I got it and then wouldn't start in the Spring. Played with it off and on all Summer with the wiring diagrams, but nothing. I finally changed the ignition switch that was suggested to me by two people and - voila! It ran. Edited June 5, 2015 by shallowwatersailor Share this post Link to post Share on other sites
doc724 925 #9 Posted June 5, 2015 Hi John,Thanks for this tip (bad ignition switch). I will add it to my diagnostic "tool kit" on the "other 416H" I have. Share this post Link to post Share on other sites
