mowerman1193 32 #1 Posted June 9 I've got a 1994 - 5 520-H that has been having starting issues.. I at first thought it was fuel / carb issues since tractor has sat around 7 years prior to me buying it. I've had it running and put a couple hours on the meter.. I started having starting issues with it and upon testing things I wasn't getting spark.. remember being told by seller that ignition switch needed replaced as it starts when it wants..In testing the spark with a lighted spark tester I found that it lite the spark tester after cranking and when I turn the key to the off position. I ordered a new switch and it's doing the exact same thing still.. sometimes it'll fire and run other times not.. turn the switch to the off position and sometimes it'll ignite the fuel in it a shoot a flame out the exhaust, LOL What are some things to look for to get this issue resolved? I suppose I could have gotten another bad switch but I'm wondering if there is some other issue going on and maybe the switch was never bad at all. Open to hear everyone's thoughts on this since I'm not the greatest with electrical type stuff..I've got a multi meter but don't really know how to use it much, LOL Share this post Link to post Share on other sites
lynnmor 7,305 #2 Posted June 10 Here would be a good place to start. After reviewing the information there, get back and let us know what you have found. Share this post Link to post Share on other sites
953 nut 55,180 #3 Posted June 10 12 hours ago, mowerman1193 said: told by seller that ignition switch needed replaced When a previous owner tells you anything only needs XXXX and it is an inexpensive item take that with a grain of salt. If it was that easy and didn't cost much he would have already done it. A bad condenser will cause ignition problems. The engine will run without a condenser, disconnect it and see if the problem goes away. If the problem disappeared get a new condenser and go on your way, if not then reattach it and move on. 520s have the infamous NINE PIN CONNECTOR that attaches the electrical system to the rest of the Wheel Horse, Check it out for corrosion or heat related damage. ONANs don't have ignition points but they do have an electronic module that does the same thing and if it or its connections are corroded it will cause intermittent ignition, they may need cleaning. The ONAN Service Manual has a good ignition diagnostic section, download it, study it, check things out and then just repair or replace the parts that are actually causing the problem. Don't just keep buying stuff until you happen to find the actual cause. 1 Share this post Link to post Share on other sites
mowerman1193 32 #4 Posted June 10 1 hour ago, 953 nut said: When a previous owner tells you anything only needs XXXX and it is an inexpensive item take that with a grain of salt. If it was that easy and didn't cost much he would have already done it. A bad condenser will cause ignition problems. The engine will run without a condenser, disconnect it and see if the problem goes away. If the problem disappeared get a new condenser and go on your way, if not then reattach it and move on. 520s have the infamous NINE PIN CONNECTOR that attaches the electrical system to the rest of the Wheel Horse, Check it out for corrosion or heat related damage. ONANs don't have ignition points but they do have an electronic module that does the same thing and if it or its connections are corroded it will cause intermittent ignition, they may need cleaning. The ONAN Service Manual has a good ignition diagnostic section, download it, study it, check things out and then just repair or replace the parts that are actually causing the problem. Don't just keep buying stuff until you happen to find the actual cause. This seller (Kelly Hollister) isn't like that and I personally know him as many on this forum do to since he sold a lot of parts previously but got out of it and sold everything off.. he went through and cleaned out the carb and got it running for me as I was originally buying it as a none running tractor but he got it going but told me the switch was funny back when he did use the tractor. I would believe this from "most sellers" but this guy isn't one of them.. he even said if I had any issues with the tractor to let him know and he'd be willing to stop by and help. I just don't want to bother him since he is really busy this time of year with racing and I like to "try" fixing things myself first anyay as that is how we "I" learn things. Thank you for the PDF info.. I'll look through this stuff you mentioned. I have heard these 520's can have some wiring issues etc.. and have their quirks and since I've not messed with them before now I thought I'd ask here as maybe this is somewhat common on these and someone might know exactly where to point me to the problem, so I guess I'll look things over good and go from there. Appreciate everyone's feedback so far.. 1 1 Share this post Link to post Share on other sites
lynnmor 7,305 #5 Posted June 10 Download the Demystification Guide so you can trace each electrical circuit. The 9 pin connector and fuse block are often the problem areas, many Wheel Horse models have those but for some reason the 520H and Onan gets all the blame. The 520H has three relays that does add complication but they are rather reliable unless connectors are corroded. If that tractor sat out in the weather all bets are off, I would never consider purchasing a weather tractor. 1 Share this post Link to post Share on other sites
mowerman1193 32 #6 Posted June 12 Was stored inside for the last 10 years I think anyway.. not sure about the owner before the last one though.. Pretty clean condition with only like 400 hours. Share this post Link to post Share on other sites
