2003 90TLRB (90Hp 2 Stroke) Timing way off

[CaptinDuck]

Hey Fellows,

I've got a 90Hp that is getting the best of me. This problem happened suddenly and I'm not sure what failed. The motor runs rough, real rough.

I checked the timing and it looks like its ~120D ATD. The timing light is lighting up the marks for cylinder 2. If I separate the yellow wires on the CDI to put it in emergency mode, the timing drops back to about 8D BTD on cylinder 1, just were its supposed to be. That and the motors runs much smoother.

I have a known good motor that I was able to do some parts swapping with. I swapped the the CDI and crank position sensor and its the same with both sets of electronics.

I'm not entirely sure what controls the firing with this motor. Is it possible something it shorted out that I haven't found? I haven't popped the flywheel to look under it just yet.

I'm hoping to get a pointer in the right direction.

Thanks

[99yam40]

I would test pulser coils.

I think the 90 had 2 ,
one told #1 when to fire and one for #3,
#2 was con*****ed by CDI

But I could be way off.
Wait on Rodbolt or Bosco99 to chime in

[rodbolt17]

depends on the year model.
without it all I can say is there were two different sytems used.

[rodbolt17]

the 2003 model uses a single pulser coil for spark on 1 and 3 and the crank position sensor and CDI for #2.
before you randomly start swapping index the flywheel. make sure 1 TDC is where its supposed to be.
then break out the handy dandy service manual and your DVM with the DVA attachment and test the system.

[robert graham]

Have you considered other problems other than electronics/timing?....like fuel delivery, fuel pump, bad spark plugs, etc., etc.....faulty/failure of the firing electronics on these motors is usually way down on the list of problems....

[CaptinDuck]

Thanks for the info fellows. The pulsor coil is where I was headed next. I should have thought to index #1 before I posted. That's first on the list when I get back in front of the motor.

One more question, how are the magnets on the flywheel secured? I'll find out soon enough when I pop it off, but thought I would go ahead and ask. I remember an envinrude a good while back that had them glued on and the magnets broke loose and moved.

Also, the fuel system is good to go. That's where I started with this problem. Really sounded like a fuel delivery problem until I slapped a timing light on it. Fresh plugs, carb kits, checked the reeds, fuel pump is pushing gas, even ran new fuel line from the tank.