Tgalo 121 #1 Posted June 28 I have a question, my restored 94 520H just shut off on me after mowing and bringing it down to idle. Crank, no start. Full of gas, checked spark but had none. Oil full. I put a air mover blowing on it for 5 minutes or so than she started. Do these things have thermal protection that I don't know about? Shes never don't this before. Now it was 98 degrees out so. Just wondering if I have something brewing... 1 Share this post Link to post Share on other sites
cleat 7,296 #2 Posted June 28 Sounds like the ignition module or coil failing (possibly the 9 pin connector). If it doesn't do it again then you are good if it does then you will need to do more testing to see which failed. Intermittent problems are the hardest to figure out. A complete failure is easier to find. 5 Share this post Link to post Share on other sites
squonk 43,939 #3 Posted June 28 If you didn't take the 9 pin connector apart during resto, dollars to doughnuts it'd shot. They have a high track record of failing. They pick up a lot of heat from the muffler. 1 Share this post Link to post Share on other sites
dkg520 527 #4 Posted June 28 Just went through the same issue with my 520-8. It was the 9 pin connector. 2 Share this post Link to post Share on other sites
Tgalo 121 #5 Posted June 29 Thank you for the replies. I had to go back and look, it was 2020 when I did it so 5 years ago. Pretty sure I did something to the connector. I remember it was melted as mentioned. I remember replacing the little fuse box because it was really bad. I will get a good look at it this week. T 1 Share this post Link to post Share on other sites
Retired Wrencher 5,837 #6 Posted June 29 What would we do “without” this site. So much knowledge here. And as most times it is the simple things that go wrong. And that is good. 1 Share this post Link to post Share on other sites
JoeM 8,429 #7 Posted June 29 Don't rule out the coil. Something quick would be to confirm spark when this happens. 1 Share this post Link to post Share on other sites
kpinnc 14,712 #8 Posted June 29 6 hours ago, JoeM said: Don't rule out the coil. Agreed. Those coils act like that when they start to fail. At first it's only when they get hot. 1 Share this post Link to post Share on other sites
Tgalo 121 #9 Posted June 29 (edited) I did check for spark, and it had none. I knew it wasn't a fuel issue because I could see gas in the filter being pumped when cranking. I might just throw a coil at it anyway... Anyone got a good source for a coil? Edited June 29 by Tgalo 1 Share this post Link to post Share on other sites
lynnmor 7,858 #10 Posted June 30 17 hours ago, Tgalo said: I did check for spark, and it had none. I knew it wasn't a fuel issue because I could see gas in the filter being pumped when cranking. I might just throw a coil at it anyway... Anyone got a good source for a coil? Why not go the the Wheel Horse Electrical topic and read before throwing parts at it? Share this post Link to post Share on other sites
Tgalo 121 #11 Posted June 30 Why? Well it’s 32 years old and I’m lazy. 🤣 Share this post Link to post Share on other sites
kpinnc 14,712 #12 Posted June 30 1 hour ago, Tgalo said: Why? Well it’s 32 years old and I’m lazy. That can get expensive. I never had issues with the 9 pin connector. What I have had issues with are key switches, coils, and plug wires. Had to replace all of them at different times on my 520-H. 1 Share this post Link to post Share on other sites
2kflhr 13 #13 Posted July 1 In 2016 I was experiencing an intermittent loss of power. Thinking it was fuel related I replaced the fuel filter, drained/flushed the fuel tank thinking it must be water intrusion. The culprit was a small piece of a plastic bag caught up in the fuel shut off valve. In 2018 I began experiencing the same thing after the engine got hot. It was an ignition coil that was failing. I converted it from the ASAM to a CDO using the ignition conversion kit 24-755-307S. Every now and again I get the "no charge" indicator light after starting but eventually goes out. Share this post Link to post Share on other sites
lynnmor 7,858 #14 Posted July 1 5 hours ago, 2kflhr said: In 2016 I was experiencing an intermittent loss of power. Thinking it was fuel related I replaced the fuel filter, drained/flushed the fuel tank thinking it must be water intrusion. The culprit was a small piece of a plastic bag caught up in the fuel shut off valve. In 2018 I began experiencing the same thing after the engine got hot. It was an ignition coil that was failing. I converted it from the ASAM to a CDO using the ignition conversion kit 24-755-307S. Every now and again I get the "no charge" indicator light after starting but eventually goes out. You should show us how you installed it on an Onan engine. Share this post Link to post Share on other sites
Tgalo 121 #15 Posted July 12 Thought I would follow up on this. I guess I got lucky. I finally got to taking a look at the 520 and found the back cylinder plug wire corroded itself into the coil. It was green and nasty looking. I ordered a coil and a set of plug wires and what a difference. Started easier and even the surging was gone. I've been fixing transmissions for 40 years now and I guess I forgot the meaning of "preventive maintenance" She even got an oil change... Thanks all Share this post Link to post Share on other sites
