JD - X485 Ignition Coil Test

[jbaker8935]

So I've got the problem where the engine starts to lose power & misfires after about 30mins of mowing. Suspect the coils, but also saw the MAP sensor thread & so I want to make sure I buy the right overly expensive part.

In the service manual it says primary coil resistance should be 2.2-3.6 k (though in another part of the manual they leave off the k).

I'm measuring 5 Meg on both. Am I doing it wrong Or is there logic in this? ie. correct reading for the symptoms I'm experiencing.
secondary on both is within spec.

I assume they are both bad, but want to make sure since they both read the same way.

 

[jbaker8935]

Replaced with new. That, along with clearing out some blockage on the radiator fixed my issue. Running much smoother, cooler with better power.

One thing though. Even new coils primary resistance didnt measure as in the manual with both my DMM (.5M) & my analog meter (20k). reading must be for their specific tool. secondary was fine though.