2002 Yamaha 70hp 2-Stroke no spark after Rebuild

[kevin11mic]

So I Bought this outboard a few weeks ago. It ran but had low compression on the bottom cylinder. The boat that the motor was on was a center console so it had the binical controls. When we took the motor off i abandoned the controls since i need side console controls. I ordered a used Yamaha 703 controller with cables off ebay. I abandoned the Tach and speedo. Hooked everything up and tilt works, motor turns over, just no spark. I must be missing something simple in the transition. I cant figure it out for the life of me. I dont think its the CDI since it was running 2 weeks ago. Any help is appreciated.

 

[99yam40]

disconnect the white wire at CDI to see if spark comes back.
key switch and kill switch ground this wire to stop spark.
Measuring peak voltages into and out of CDI will tell you if those coils and CDI are putting out the voltages they should be.

not sure I would be putting a lot of money in a motor that has low compression on a cylinder or did you some how fix that already

 

[kevin11mic]

disconnect the white wire at CDI to see if spark comes back.
key switch and kill switch ground this wire to stop spark.
Measuring peak voltages into and out of CDI will tell you if those coils and CDI are putting out the voltages they should be.

not sure I would be putting a lot of money in a motor that has low compression on a cylinder or did you some how fix that already

Il try this out asap. I already rebuilt the engine so I lost spark through reassembly. Being that it is a different set of controls i would like to think that is where the issue is. Il follow up after i try this tonight.

 

[kevin11mic]

Tried disconnecting the white wire and no luck. I pulled the flywheel off and found the charge coil has a little torn spot on it and with closer inspection a little white wire under the surface of the coil insulation was broke/shorted. Tried to fix it but wires are too small so I ordered a charging coil. Could this be causing no spark?

 

[flyingscott]

Is the tether connected to the switch on the control

 

[kevin11mic]

Is the tether connected to the switch on the control

Yes, and to rule out a malfunctioning switch I disconnected the wire going into the CDI box. Still no spark. Hoping the bad charging coil is my problem

 

[99yam40]

Tried disconnecting the white wire and no luck. I pulled the flywheel off and found the charge coil has a little torn spot on it and with closer inspection a little white wire under the surface of the coil insulation was broke/shorted. Tried to fix it but wires are too small so I ordered a charging coil. Could this be causing no spark?

Charge coil is what produces the voltage to CDI that it sends on to the ignition coils

As I said testing/Measuring voltages into and out of CDI leads you to where the problem is located
no voltage in means no voltage out

 

[kevin11mic]

Charge coil is what produces the voltage to CDI that it sends on to the ignition coils

As I said testing/Measuring voltages into and out of CDI leads you to where the problem is located
no voltage in means no voltage out

Sounds like that may be my issue (hopefully). I guess I damaged the coil in break down or reassembly. I'll follow up after I install the new charge coil and check input and output voltage.

 

[99yam40]

threading bolts too far into flywheel for puller can damage coils under it

 

[kevin11mic]

threading bolts too far into flywheel for puller can damage coils under it

Now that you say that. That is exactly what happened! Need to make sure I didn't damage one of the other two.

 

[kevin11mic]

Also, when troubleshooting i noticed the yellow wire loop comming off the CDI. Emergency circuit wire. Is this supposed to be hooked up anywhere. how does the emergency circuit work?

 

[kevin11mic]

New Charge coil fixed the issue. Thanks for all the help!