Ignition coil testing

[RBudd]

Hi All,

Have a question about testing an ignition coil off a Dolmar saw which I suspect may be faulty.

Have checked with an in line spark tester and could see no spark, although the same tester, which is a bulb type, does not light up on other machines I have which run well so I suspect that tester requires a very strong spark. Are the testers with a variable gap much better?

Next checked with a multimeter, and the resistance across the secondary coil was about 2500 ohms when using a 20k ohm scale, which seems a little low to me? Have searched for similar threads but didn't find much mention of coils with lower than expected resistance. My experiences with other healthy coils seem to be about the 9000 ohm mark, so is it possible this coil is shorting across the turns in the secondary coil somewhere giving lower resistance and thus very weak spark?

Cheers in advance for any advice!

 

[HarleyT]

Just unscrew the plug, and fasten the coil wire plug on a new spark plug. Disconnect the kill wire to the coil. Then ground the metal side of the plug on the metal of the block and pull the rope in a dark room. If you have no spark, then the coil is bad....

 

[Landmark]

Just pull the wire off and hold it while someone pulls the rope. Might take a couple tries to make sure its hot enough.