Coil Ohm Specs

Ford 2000; 3 cyl. gas; 4/1 Trans; 12v....Have been having a lot of trouble getting my tractor cranked lately and took the coil off and tested it, among other things. The results were 1.6-1.9 ohms across the + and - terminals and 7280 from the wire hole to each of the + and - terminals. I couldn't find anything about what an acceptable level of ohms is for the coil that was on the tractor and am hoping someone may know or can tell me if the coil is within specs with those readings.

The coil has worked fine in the past so wondered if a bad coil might be the culprit in my starting woes. I have not yet done a spark test but thought I'd pose the ohm question because I'd like to know the ohm spec for the coil so I can write it in my manual for future reference. The coil part number is ABC509 12v and, according to a tractor supply house, is the correct unit. Thanks for any input you can provide.
 
I think your numbers are good. As I recall the turns ratio of the coil (transformer actually) is 1800:1. The wire size is much smaller on the
secondary (high voltage) so you can't do an ohm to ohm comparison.

The primary circuit should be resistively limited to 5 amperes max. per a MF 35 service manual that I have.....nothing unique to MF. They
used the same parts as others to do the ignition so if 5 amps was max for theirs it should be a good number for all in my (humble) opinion.

So add a resistor (ignition, high dissipation type) to the primary circuit for your 5 amperes. Not knowing your mental resources, take your
running DC voltage (13.5?) divide by 5 and that's your series resistance minimum requirement.
 
You will find a resistive wire (not discrete resistor) in the primary circuit of those thousand series 3 cylinder tractors. About 1.3 to 1.6 Ohms.
 

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