Testing coil

Gene Martin

Recruit
Joined
May 15, 2004
Messages
3
Is there a way to check the coil on my engine or should I just replace it? I have put a new cap, rotor and plug wires on and wondering if I should replace the coail as well. No way of telling how many years its been on.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,399
Re: Testing coil

VB - You can usually check a coil using a voltmeter. One "side" of the coil is usually grounded to the block. Disconnect the coil from the powerpack and the ground. Check the resistance value across the primary winding (the two non-spark plug wires). The resistance should be very small (~1 ohm), but not a direct short. Then check from the primary side of the coil to the coil's metal case. There should be no continuity.<br /><br />Then check the resistance across the secondary winding (spark plug cable to grounded side of the coil. The resistance should be high, but measureable (a manual will give a range of ohms) Then check continuity from the spark plug cable to the coils metal case. Again it should be none. If the coil is encased in plastic, look for cracks and leakage of oil.
 
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