Causes of weak spark on Tohatsu 18HP 2-stroke?

[pvanv]

Re: Causes of weak spark on Tohatsu 18HP 2-stroke?

What does this look like when compared to the specs in the service manual?

 

[32bit.flannel]

Re: Causes of weak spark on Tohatsu 18HP 2-stroke?

What does this look like when compared to the specs in the service manual?

I don't understand what the specs in the manual are asking for in regards to the CDI...that's why I'm here.

As for the magneto there are two sets of specs for each coil. The exciter is good on the higher value spec. The trigger is a bit higher than the high spec (60 vs 30), however the trigger seems to be working because I'm getting pulses a bit over 150V out of the wire from the CDI to the coil. The strange part is that 150V vanishes once I connect the CDI to the (brand new) coil.

So basically I'm back to where I was when I decided to replace the coil, where I have power output that should be getting to the coil but it vanishes once connected to the coil (and with 0V output from the coil). If that high resistance value at the trigger coil can cause exactly what I've described then yeehaw, however I don't understand how that would cause the failure if I have voltage out the CDI (my understanding is that the primary charge should be from the exciter coil).

Thoughts?

 

[pvanv]

Re: Causes of weak spark on Tohatsu 18HP 2-stroke?

If you have great output from the CD until you connect the load (ignition coil), and it drops to 0 volts when connected, then one of 2 possibilities is the case: either 1- the coil has a near short, causing the incoming signal to drop, or 2- the CD does not have adequate drive to maintain the voltage when the correct ign coil is attached. So... verify the coil primary impedance, and if OK, you probably need a CD.