Keith 21 #1 Posted December 9, 2018 520H runs smooth for a few minutes then dies like switch was cut off. Starts again and will run for a minute or two then dies again. The previous owner said he replaced an ignition module last summer, for this reason. Apparently that wasn't the cause of the stalling. Are there electrical diagnosis procedures for this engine? Share this post Link to post Share on other sites
bc.gold 3,399 #2 Posted December 10, 2018 6 hours ago, Keith said: 520H runs smooth for a few minutes then dies like switch was cut off. Starts again and will run for a minute or two then dies again. The previous owner said he replaced an ignition module last summer, for this reason. Apparently that wasn't the cause of the stalling. Are there electrical diagnosis procedures for this engine? From the symptoms your describing, I'm placing my bet that the insulation inside the coil has deteriorated with age or possibly using a coil with out a ballast. Most modern ignition coils have an internal ballast. From the engine manual find out how many ohms are specified then from the instructions given and a cheap ohm meter check your coil to see if its within spec. Also you could remove the high tension wire from a spark plug then observe the color of the spark any thing other than lightning blue change the condenser. While you have the points cover removed check to see if the points move freely and that the face of the contacts align properly with each other. Share this post Link to post Share on other sites
Tinbender 5 #3 Posted December 10, 2018 (edited) Post the model and serial numbers of your tractor, it will aid those wanting to help you. Find your engine manual here: https://www.wheelhorseforum.com/files/category/14-onan-service-manuals/ Insure the manual covers your engine model and serial number. I'm with bcgold, your problem does sound like a bad coil but DO NOT replace the coil until you verify it is bad, they are not cheap. The engine manual covers how to test the primary and secondary coil windings of the coils using a multi-meter, even a cheap Harbor freight multi-meter will do the job. The rear spark plug wire, nearest the seat, can fail do to heat and ground out to the frame. To eliminate this as the problem, wrap the plug end of the spark plug wire with electrical tape, especially any portion that contacts frame. Edited December 10, 2018 by Tinbender 1 Share this post Link to post Share on other sites