# Tecumseh hs50 coil question



## tmiller (Dec 30, 2005)

Does anyone know how to test a coil using a voltmeter? I am working on my old Ariens snowblower with a 5hp Tecumseh motor. After rebuilding the internal engine, I got it to fire one time, but before I could adjust the carb, it died and has never since sparked. This is a model with an internal ignition and some of the laminated plates are slightly bent. I looked into getting a new stator plate because the laminations are riveted on, but the part is no longer available according to Tecumseh. I cleaned the plates and magnets and gapped the points. The points and condenser look good (I know you are going to recommend replacing them as well as the spark plug). I noticed a crack in the coil ground lead, so I soldered on a new lead. After that I was checking to make sure the kill switch was not grounding out and noticed that the ignition was always grounded to the crankcase. I removed the kill switch, but it is still grounded. Finally, I found that the coil primary lead and coil ground lead are continuous and both are partially continuous with the high tension lead. I am just guessing, but I think this is not normal. In this state, the ignition is constantly grounded because the coil ground lead grounds the entire ignition. Final question, in my observation I discovered that normally when the points are closed the ignition is grounded temporarily to the crankcase and when the points open the current is redirected to the spark plug. Is this a correct observation? Thanks in advance for any help.
Todd


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## mikemerritt (Dec 6, 2004)

Test the coil with your volt meter using the ohm setting. Ground to the coil base and hot to the plug wire. NOTE: this is not a very precise way to check a coil because all this does is test the continuity of the windings. The continuity is subject to change as the coil warms or cools. 

I'm sure this coil is supposed to be grounded. Newer magnetos have a ground tab that is soldered to the armature therefore grounding through the base to the block. I think this system has real ground wire and that may be what you are seeing. Forgive my inability to remember exact details, its getting to the point that I only fool with these a time or two a year. 

My shot in the dark on this is a bad condensor. From your description thats where I would throw 3.00.

Mike


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## tmiller (Dec 30, 2005)

Thanks for the response. There are 3 leads coming from this coil. There are the Ground Lead, the Primary Lead (which connects to the points terminal) and the High Tension Lead (aka Spark Plug Wire). When I tested it, there is no resistance between the Ground and Primary Leads, which is why I thought the coil was bad. There is 8 ohms of resistance between each of these leads and the High Tension Lead.
Todd


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