1990 Yamaha 200ETXD No Spark Half Cylinders

[niceoldgrady]

I have a 1990 Yamaha 200ETXD which is only firing on the three right cylinders. The three left cylinders have no spark. I confirmed this using an old automotive timing light. Flashes on all three right plug wires and none of the left plug wires. I also removed all three plug wires of left side and engine still started and ran as it did before.

This 200 HP motor is on a 19' Grady White Tournament which I do not run hard. I noticed it running rougher than usual but I guess it has so much power in relation to the boat it is pushing it still motivated the boat along okay. I am amazed that this motor idles with three cylinders not firing.

1.) The ground between the cylinder head and block was cleaned and checks good.
2.) Checked for spark with motor in gear, no change. So must not be dropping three cylinders in neutral as a normal thing.
3.) All pulser coils have continuity and measure approximately 313 ohms
4.) One charge coil (Br and R) measures 736 ohms. The other charge coil (Bl / BkR) measures 73 ohms.
5.) All spark coils check good with an ohm meter.
6.) Compression 110 - 120 on all cylinders.

I am thinking that one of the charge coils is the issue given the difference in resistance. Interested in opinions or if anyone else has run into this. Could it be the CDI unit or charge coil? I notice there are two charge coils? Could it be that each is assigned to a bank of cylinders?

Any help / experience is appreciated.

 

[niceoldgrady]

So after some additional reading, if I understand correctly there are two charge coils, one for low speed and another for high speed. Perhaps this explains the difference in resistance. Anybody know about this? If this is the case then yes perhaps the CDI unit. Would like to be sure before dropping that amount of cash...

 

[99yam40]

find the service manual for your motor .
It will have the test procedures and specs along with what test equipment you will need to test

 

[jerryjerry05]

Go to outboard ignition .com
Look up the parts for the 200 Yam
Look up the individual part, stator. pack or regulator..
It will have a link to troubleshooting the main components.
Maybe CDI ignition Both have info on troubleshooting your motor.
Good uck

 

[niceoldgrady]

I obtained a manual and after reading have concluded, based upon resistance measurements, that the charge and pulser coils are good.

At this point is seems that the problem is pointing to the CDI unit.

Before I drop $850 on a unit it would be good to know if the Yamaha for some reason does not drop three cylinders as a normal thing at idle. I have read nothing to indicate this and see nothing in the schematics. Anybody know if all six should fire at idle? I think so?

Pulser coils measure approximately 313 ohms, good range 256 - 384 ohms
Charge coil low speed (Br and R) measures 736 ohms, good range 592 - 888 ohms
Charge coil high speed (Bl / BkR) measures 73 ohms, good range 55 - 83 ohms

Tried outboard ignition.com but no info on my particular motor.

 

[99yam40]

I prefer the peak voltage readings instead of ohms.
If good voltages into CDI and bad coming out then I would think CDI bad.

Might try a spark tester to make sure there is not spark, they make them so you can test all the plug wires for spark at the same time.

I have had problems with direction of pick up on timing lights before, had to turn it in opposite direction as the arrow on the head for it to work properly