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takoateli
12-11-2010, 10:46 AM
A friend's DT15 has an ignition problem, no spark period. If I put my volt meter on his induction coil (disconnected from the ignition system) I get around 15 VAC when the motor's pull starter is pulled. I've checked this with another DT15 and that seems right. When I check the voltage of the output of the little black box (the wires that go to the ignition coil, with the ignition coil disconnected) I only get a few tenths of a volt. I've checked this with a few other little black boxes here (none are known good, but at least two are suspected good) and I get the same reading. When I connect the whole ignition system and pull start the motor I get no spark. Measuring from one high voltage spark plug connection to the other I only get a few volts.

Does anyone have any troubleshooting tips I can perform using a digital VOM?

A known good motor should be back in a day and I can pull parts off that and start swapping parts. But I would like to know for future reference if anyone has any troubleshooting tips besides swapping parts.

Thanks!
Greg

takoateli
12-14-2010, 10:25 AM
Today I used a working motor and got some measurements. Here's the difference between the two motors:

Working
Stator (pickup) open circuit output voltage: 35VAC
Stator (pickup) output current: around 35mA

Black Box open circuit output voltage: 35VAC
Black Box output current: around 35mA

Non working
Stator (pickup) open circuit output voltage: 15VAC
Stator (pickup) output current: meter indicates 0

Black Box open circuit output voltage: 100mV
Black Box output current: 0

On the non-working stator the resistance indicates in the megaohms. I wish I had checked that first. Obviously that should be very low, a few ohms at most.

I'm hoping the flexible leads of the stator are damaged and I can repair it.

Greg