starting problems

circleburner12 · Post by **circleburner12** » Mon May 21, 2012 8:36 pm

im not getting any fire to the plugs, very little if any at times. new dist cap, points,plugs, condenser. timing is correct, per the tm's. the coil is used and thats what we are leaning towards is a bad coil. any ideas???. thxs

Post by **wesk** » Mon May 21, 2012 10:19 pm

Either ohm out the coil, do an amperage draw check on the coil, or take the coil to a shop with a coil tester.

circleburner12 · Post by **circleburner12** » Wed May 23, 2012 2:58 pm

how do you do a ohm test on the coil, bench test or i can hook the batts up if its better that way. ive look through the manuals and cant seem to find a how too. all i can find is to test the coil with suitable equipment!. ive also look search funtion several pages of it all i see is everthing but what im looking for or not a clear way of testing a coil. and no i dont have a coil test place around me. if anyone can help me out, please pm me with a simple way to test this coil. thxs

jimm · Post by **jimm** » Wed May 23, 2012 6:26 pm

An automotive coil is actually a transformer with two coils in one package: a low voltage primary coil with few turns, and a high voltage secondary coil with many turns. Both coils share a common input terminal; the output terminal of the primary coil goes to the points and from there to chassis ground, the output terminal of the secondary coil is the high tension lead to the distributor. Checking input to output of each coil with an ohmmeter, you should have continuity (no open circuit, or infinite resistance), and somewhere around 1000 times more resistance on the secondary than on the primary (due to the more turns), and neither should be zero resistance. You need a decent ohmmeter, though, because the primary coil resistance is only somewhere around 1 Ohm. I don't know the numbers for the 24V coils used on our MVs, but here is an example for a "typical" automotive coil: http://www.international-auto.com/fiat- ... n-coil.cfm

circleburner12 · Post by **circleburner12** » Wed May 23, 2012 7:42 pm

thxs jim, went and pick up a tester and tested the coil. if the selecter switch is in the correct position, by coil is reading 0.0 for the primary and 11.0 for the secondary. so would it be correct to assume the coil is bad??. thxs

Post by **wesk** » Wed May 23, 2012 8:07 pm

The how to is clearly shown in TM 9-1825B which is free for you to download from our downloads page. Coil testing has been covered in at least 10 or more posts the last two years.

I've had this photo on the album page for 5 or 6 years.

If you test was performed correctly and the tester had the necessary accuracy level then you have a shorted primary circuit.