aamyot
Cadet
- Joined
- Nov 14, 2009
- Messages
- 26
I could use some help determining what part has failed on my old 1986 Suzuki DT40CT (Ser# 04003-610506) before I go buying expensive, out of production parts until I get it right.
The engine started acting funny at WOT, surging the RPM down, then back up after a couple seconds. It did this multiple times until I slowed down. At idle, it also acted funny, with irregular firing, until it just turned off and would not start.
I managed to get home on the trolling motor and used a spark tester to find there was no spark on either of the 2 wires. The engine turns over quite excitedly, so starting battery is not the issue. I checked the kill switch circuit and found it operating fine. I disconnected the kill switch at the CDI to be sure.
I tested all the coils in the magneto using the specs in the service manual and came up with the following:
Secondary Coil Resistance: 2600 Ω (Spec 2300-3100)
Condenser Charge Coil Resistance 296 Ω (Spec 230-280)
Timing Coil 210 Ω (Spec 175-210)
Lighting Coil 2.5 Ω (Spec 0.20-0.25)
The Charge Coil Resistance is a little higher resistance than spec, but I would imagine it would still send enough current to at least get a small spark.
The Lighting Coil is certainly way out of spec. Is that my issue?
Is this just the CDI module gone bad? I've looked up how to test it, but everything I found was troubleshooting the parts around it rather than the unit itself. Is this the way to do it?
I would like to test the output of the magneto coils and I have a DVA adapter, but I don't have the specs. I suppose I'll test it anyway and post it when I get back to it.
Thanks for any insight
The engine started acting funny at WOT, surging the RPM down, then back up after a couple seconds. It did this multiple times until I slowed down. At idle, it also acted funny, with irregular firing, until it just turned off and would not start.
I managed to get home on the trolling motor and used a spark tester to find there was no spark on either of the 2 wires. The engine turns over quite excitedly, so starting battery is not the issue. I checked the kill switch circuit and found it operating fine. I disconnected the kill switch at the CDI to be sure.
I tested all the coils in the magneto using the specs in the service manual and came up with the following:
Secondary Coil Resistance: 2600 Ω (Spec 2300-3100)
Condenser Charge Coil Resistance 296 Ω (Spec 230-280)
Timing Coil 210 Ω (Spec 175-210)
Lighting Coil 2.5 Ω (Spec 0.20-0.25)
The Charge Coil Resistance is a little higher resistance than spec, but I would imagine it would still send enough current to at least get a small spark.
The Lighting Coil is certainly way out of spec. Is that my issue?
Is this just the CDI module gone bad? I've looked up how to test it, but everything I found was troubleshooting the parts around it rather than the unit itself. Is this the way to do it?
I would like to test the output of the magneto coils and I have a DVA adapter, but I don't have the specs. I suppose I'll test it anyway and post it when I get back to it.
Thanks for any insight