1987 Suzuki DT25 missing parts of the wiring harness, cdi ignition

[dockrat100]

I recently obtained a 1987 Suzuki DT25 that the previous owner said was not getting spark to the top cylinder. He correctly surmised that it was missing part of the CDI ignition system, as the rectifier is missing. Upon inspection, I also noticed that one of the ground wires had shorted out and cooked itself. What could go wrong with the rectifier that could possibly cook a ground wire? Or what should I be looking for to find the source of short?

Also, does anyone have wiring diagrams for this motor? I have too many wires under here to figure out where they all go. I have included a few pics to show what i am dealing with.

 

[Silvertip]

Re: 1987 Suzuki DT25 missing parts of the wiring harness, cdi ignition

An electrical problem somewhere other than the rectifier may have fried the wire. Electricity is funny in that it makes its way back to the negative terminal of the battery via any path it can find. If the current level is high enough, small ground wires will melt. Case in point -- DON'T DO THIS but if one removes the big negative battery cable but you leave all others that may be present connected and then try and start the engine, smoke will rise from somewhere in the boat/engine. Other smaller ground connections will attempt to carry the high starter current load which they are obviously not capable of carrying.

 

[dockrat100]

Re: 1987 Suzuki DT25 missing parts of the wiring harness, cdi ignition

This particular motor does not have a starter, but I see your point. I am very new to CDI ignition, so I do not see what other current would have been adequate to cook the ground wire. I can replace the ground wire, but I don't know if I am throwing good money after bad.

 

[Silvertip]

Re: 1987 Suzuki DT25 missing parts of the wiring harness, cdi ignition

Throwing good money after bad????? Wire is cheap.

 

[dockrat100]

Re: 1987 Suzuki DT25 missing parts of the wiring harness, cdi ignition

I also would need to replace the rectifier. Besides the other things that are broken that I haven't found yet. I am still trying to decide if this motor is worth restoring or if it should be parted out.

 

[99yam40]

Re: 1987 Suzuki DT25 missing parts of the wiring harness, cdi ignition

Not sure about your Suzuki, but manual start motors usually are not set up with battery charging components like rectifier/regulator and lighting coil to produce the voltage for battery charging.
CDI stands for Capacitance Discharge Ignition.

As I said before not sure about that old Suzuki ,but most will have a charge coil for charging capacitor and a pulsar coil to tell it when to discharge the cap into the coil to fire plug. You need to find out for sure what motor it is and find a service manual for it.

See if this will help you under stand some of the testing of CDI ignitions

http://www.outboardparts.com/troubleshooting/printguide.htm