1981Scout 3 #1 Posted May 8 Hey all, new guy here. I've always creeped the forum to help with my WH problems but i'm stumped on my current situation. My 1993 416h with Onan p216g has me baffled. I'm loosing spark randomly, sometimes after 2 minutes sometimes after 10 or 15. Coil checks out good and i even tried a good spare. So here is my question, can an ignition module test good, but then fail when warm ? I did the multi meter test and it does switch back and forth BUT, i am not getting 1-1.5v, i am getting .86-.93 ish bolts. Not sure how critical that is, i believe my meter is accurate. Also i pulled the ignition module and wired up a tail lamp like i read to do on this forum, and it does in fact light the lamp with the rotor. Hate to buy a new one if not needed. thanks all Share this post Link to post Share on other sites
1981Scout 3 #2 Posted May 8 I actually thought i had solved my problems by replacing my negative battery cable. Thought it was a ground issue, but i was wrong. Share this post Link to post Share on other sites
cafoose 3,355 #3 Posted May 9 Mine failed when warm. Sounds like the same problem I had. I replaced the module and everything was great ever since. 2 Share this post Link to post Share on other sites
lynnmor 7,308 #4 Posted May 9 Yes, the module can become temperature sensitive. Later models have a gasket material behind the module to help prevent heat transfer from the engine block but they only help a little. Be sure to check the wiring, ignition switch and fuse holder before going any farther. 1 Share this post Link to post Share on other sites
1981Scout 3 #5 Posted May 9 thanks fellas, i will bite the bullet and order a new module. 1 Share this post Link to post Share on other sites
1981Scout 3 #6 Posted May 9 i did not check the ignition switch yet. i will do that first . need to find out how to do that. 👍🏻 Share this post Link to post Share on other sites
lynnmor 7,308 #7 Posted May 9 47 minutes ago, 1981Scout said: i did not check the ignition switch yet. i will do that first . need to find out how to do that. 👍🏻 Download the Demystification Guide so that you can see each system separately. Using a voltmeter, connect to the various terminals and jiggle wires and the key to see if there is an intermittent connection. Any connection can benefit from taking it apart and cleaning with a small toothbrush size wire brush. Coating the connection with No-Ox-Id will prevent future oxidation. Share this post Link to post Share on other sites
1981Scout 3 #9 Posted May 14 On 5/9/2024 at 7:15 PM, lynnmor said: Download the Demystification Guide so that you can see each system separately. Using a voltmeter, connect to the various terminals and jiggle wires and the key to see if there is an intermittent connection. Any connection can benefit from taking it apart and cleaning with a small toothbrush size wire brush. Coating the connection with No-Ox-Id will prevent future oxidation. to be completely honest i feel i'm a pretty decent mechanic. both my sons race motocross and i have no problems wrenching and rebuilding. But when it comes to reading and understanding electrical circuits and diagrams i have MUCH to learn. I was looking at the spark circuit in the demystification guide and it is clear as mud. I need to get better because i'm sure this would make my life easier. I have some buddies at work who are both electricians and or engineers to help me understand what exactly i am looking at and to help me understand. my 416h serial 2000350 model 51160E02 im gonna purchase the ignition control module and rotor, and i'm gonna throw a new ignition key switch in also. I hate throwing money without being positive it's what i need but at home we are tired of push mowing our 3 acres. Can someone gimme a cross number of some sort for the ignition key switch ? I think it is Toro 116338 but i am not positive. Thanks so much everyone Share this post Link to post Share on other sites
lynnmor 7,308 #10 Posted May 14 3 hours ago, 1981Scout said: to be completely honest i feel i'm a pretty decent mechanic. both my sons race motocross and i have no problems wrenching and rebuilding. But when it comes to reading and understanding electrical circuits and diagrams i have MUCH to learn. I was looking at the spark circuit in the demystification guide and it is clear as mud. I need to get better because i'm sure this would make my life easier. I have some buddies at work who are both electricians and or engineers to help me understand what exactly i am looking at and to help me understand. my 416h serial 2000350 model 51160E02 im gonna purchase the ignition control module and rotor, and i'm gonna throw a new ignition key switch in also. I hate throwing money without being positive it's what i need but at home we are tired of push mowing our 3 acres. Can someone gimme a cross number of some sort for the ignition key switch ? I think it is Toro 116338 but i am not positive. Thanks so much everyone Parts information from Toro is available here. Note the tractor model number is slightly different that what you wrote. Download the Onan Service Manual here, it will have the instructions for testing parts. The Demystification Guide is incorrect, the Breaker Points should say Ignition Module. All you need to know is that there is 12 volts at the + terminal on the coil when the ignition switch is in the run or start position. You can run a wire from the battery + to the coil + for testing purposes, just don't leave it connected any more than necessary. Share this post Link to post Share on other sites
1981Scout 3 #11 Posted May 15 i've been checking all my wiring. ugh, yuck. is it possible to just rewire this machine minimally. As in wire it up to run with nothing additional like indicator/warning lights, headlights/tail lights, basically eliminate everything that is not necessary for the machine to run and mow ? All i need is a mowing machine ! Share this post Link to post Share on other sites
lynnmor 7,308 #12 Posted May 15 11 hours ago, 1981Scout said: i've been checking all my wiring. ugh, yuck. is it possible to just rewire this machine minimally. As in wire it up to run with nothing additional like indicator/warning lights, headlights/tail lights, basically eliminate everything that is not necessary for the machine to run and mow ? All i need is a mowing machine ! Look again at the diagram above, it is about as simple as it gets. Share this post Link to post Share on other sites
1981Scout 3 #13 Posted May 20 just wanted to update and tell you all that my wheelhorse is up and running again. My ignition module was my culprit. Also wanted to tell you that my old module did and does still test good. So i would assume that it is temperature related and it fails to work when hot. One of these days i may wire it up to a tail lamp and hit it with a heat gun to see if it fails. Also rewired some things that looked like they needed some attention. Ordered all my parts directly from Cummins and they arrived less than 24 hours. I was going to order from OnanParts as i see suggested on this site but i don't like the fact that electric parts cannot be returned at all even if unopened. Atleast that is the way i understand the return policy. Thanks all Share this post Link to post Share on other sites
cafoose 3,355 #14 Posted May 20 3 hours ago, 1981Scout said: My ignition module was my culprit. That's what my problem was. I think it's the most common cause and most difficult to get to especially those engine tins Share this post Link to post Share on other sites
