Coil Testing with Multimeter?

[HansFranz]

My Dolmar PS-3410TH has weak or absent spark. Replaced spark plug, nogo. Took switch out of the circuit, nogo. Most of the time it won't fire at all (I pulled plug and tested), but occasionally I can get it to start for maybe a quarter of a second, then it quits. (This is always with a cold saw, since I haven't had it running for longer than 1/4 second in months.)

The parts diagram shows two items labeled "ignition coil" -- items #121 and #130 in diagram below.

These parts are all-but-unavailable online ... although you can get "both" for $110 from an ebayer in Estonia.

Before I waste $110+ on parts I don't need for a 17-year-old saw, is there a way I can test these coils with a multimeter?

I searched "how to test a chainsaw coil" online, but all I'm finding is copypasta gibberish and AI GIGO.

Thanks in advance for any clues.

 

[ZeroJunk]

Loosen and tighten the screws that hold it. The resistance on a good ohm meter between metal on the coil and case should be close to zero. Check resistance between kill wire terminal and case. Should be several K ohms unless the wire is shorted somewhere.
With the kill wire disconnected and the coil laminations common with the case and it still won't fire, doesn't leave much else.

 

[echomeister]

Testing coils is more difficult these days, because technology ....

Old school coils were just two copper winding, primary was a couple hundred turns of wire. Ohm reading 1 - 5 ohms.
Secondary was 10k turns of very fine hairlike wire Ohms 100 - 2k ohms.

But the engineers couldn't stand it. They added electronics inside the guts. Cant do simple tests anymore. I bought 4 ignition coils for my Rav4
cause they ohmed open on the secondary. They did that because there are strings of diodes in them now. $$$$ -> drain.

If you are getting no spark and the magnets are strong on the rotor there isn't much else to be wrong except the coil.