OllieThePom 0 #1 Posted November 26, 2019 Hi, First time poster, I have a 724-Z zero turn mower which wouldn't start, tested the coil and got within specification resistance on both primary and secondary circuits but still would only spark when I released the key from cranking. I suspect the ignition module is not triggering the coil properly as the coil begins to get hot after a while (not running) as if it is being powered up continuously. In a separate test to eliminate coil failure I connected the coil to a coil pack on my car (which was running) and when i cranked the lawnmower it would run (albeit not amazing). My questions are: Does anyone know what the ignition module resistance should be as i cannot find specifications? (part number 166-0785). and secondly, am I able to fit an aftermarket ignition module from a motorbike or other mower and make it work? as I am struggling to find anywhere in Australia which is able to supply me with a new ignition module. Thanks, Ollie. Share this post Link to post Share on other sites
lynnmor 6,699 #2 Posted November 26, 2019 The module will switch on and off when the engine is rotated if it is working. I don't know of a meter reading that is useful. Is there a chance that the wiring is connected backwards supplying 12 volts to the wrong module wire? You might have luck finding a module at a shop that repairs generators. Share this post Link to post Share on other sites
ebinmaine 62,338 #3 Posted November 26, 2019 from the other side of the world. I'm not familiar with that model so take my answers as suggestions not solutions. Have you done a continuity test on the KEY SWITCH to verify correct operation? As to parts availability, I do realize the geographical difference and time involved but can you order online from other countries without incurring great additional costs? Share this post Link to post Share on other sites
Burnerman 758 #4 Posted November 26, 2019 What engine? I have a 2011 24 hp Briggs and Stratton that uses magnetos for spark. There is no12v power needed. There is 1 wire connected to the coils that when grounded will kill the spark and ungrounded will allow spark. Share this post Link to post Share on other sites
953 nut 51,014 #5 Posted November 26, 2019 We have engine service manuals for several different brands of engine located in our Manuals section, let us know what manufacturer engine you are working with and we can probable provide more information. Share this post Link to post Share on other sites
lynnmor 6,699 #6 Posted November 26, 2019 I believe that the 724-Z uses an Onan engine. The (part number 166-0785) is the number for an Onan engine module. The part is readily available, but expensive, up here where the toilet flushes clockwise. One source. Share this post Link to post Share on other sites
Stepney 2,312 #7 Posted November 26, 2019 My 516h had this exact issue. Not sure what engine exactly you have or how it works. But on mine, (an Onan) I ran power from battery + to coil + as per the troubleshooting manual. It always started right up. The key switch was shot and only sent power in the run position, but not when cranking. Share this post Link to post Share on other sites
OllieThePom 0 #8 Posted November 26, 2019 Wasn't expecting 6 replies already. Thanks. Lynnmor - I have downloaded all wiring diagrams I can find and ignition red to coil + and ignition back to coil -. Ebinmaine - I'm semi-confident that the module is at fault as I can start and run the mower if I use a different vehicle to act as the trigger, it sounds dodgey but it worked and the motor ran for 10-15 seconds with some fuel tipped into the carby. The part I need (166-0785) is minimum $109(USD) which is $160 Australian and doesn't include shipping. Burnerman + 953 nut - It is an Onan twin cylinder. Not sure of the exact engine model, but somewhere in P216, P218, P220, P224 I think. Stepney - Yeah I did that earlier as per the service manual and didn't help. Ive checked the wiring with on the mower and all seems to check out. My next plan to try and keep repair costs down was to swap the module for a Honda motorbike equivalent, but they come in 100Ohm, 300Ohm and 500Ohm from my local dealer and I have no idea which one would be best suited. Thanks guys. Share this post Link to post Share on other sites
OllieThePom 0 #9 Posted November 26, 2019 I also just did this test and it lit the globe as it passed the magnets which really throws a spanner in the works. Share this post Link to post Share on other sites