OHMS

[David C]

Happy Thanksgiving to all! My latest project is evinrude 4404 zephyr a friend gave me.It has no spark.I not sure how to test the coils as they have two plug leads on one coil.I get no ohms from plug wire to groung on any but get 7000ohms on my fluke from plug wire to plug wire on on the same coil.Both coils test close to the same.What is the right way to test these coils.Thanks Dave R

• This topic was modified 2 years, 4 months ago by David C.

[Mumbles]

Terminal to terminal is the way to test the secondary windings as the coil itself is composed of two smaller coils which are joined together internally.. Both terminals fire at the same time so both spark plugs must be hooked up to complete the circuit. I’d say your coils are good at 7K ohms.

The copper wire coming out at each end are for the primary windings. One goes to ground and the other goes to the points. Testing these leads should give an extremely low ohm reading.

• This reply was modified 2 years, 4 months ago by Mumbles.
• This reply was modified 2 years, 4 months ago by Mumbles.

[outbdnut2]

If the resistance reads abnormally high or low, yeah it’s probably bad, but if the resistance is correct, the could still can have internal insulation breaking down bleeding off the spark voltage. A high percentage of coils fail this way. Best way to check is to swap in a new coil, of if one cylinder is dead, swap the coils between the cylinders and see if the problem moves to the other cylinder.
Dave

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