View Single Post
  #2   Report Post  
posted to rec.boats.cruising
Wilbur Hubbard Wilbur Hubbard is offline
external usenet poster
 
First recorded activity by BoatBanter: Feb 2007
Posts: 2,869
Default Yamaha Enduro 2 Stroke Stator Problem


"GeoffSchultz" wrote in message
oups.com...
I am cruising in the Caribbean and just happened to be in a location
with Internet access. I only expect to have Internet until Saturday
noon, so if anyone can provide help in this period, I would be very
appreciative.

I have a 15 HP Yamaha Enduro 2 stroke outboard which is about 5 years
old. It's always run like a champ. Today when I went to start it, it
wouldn't even begin to start. I'm not well versed in the terminology
of outboards, so please bear with me. I am a good trouble shooter.

There's plenty of fuel available at the carburetor.

I don't see any spark at the plugs.

The cut-off switch appears to be working fine. It's open when the
"key" in installed and closed when pulled.

I believe that the power source for the plugs is called a stator and a
rotator. There are 2 wires coming from the stator assembly, but I
don't see any voltage coming from them. I've tried jumping them to
ground and I see no spark. The sealed unit that they lead to is
labeled "63 V", so I'm assuming that the input is 63V and that I
should be able to see a spark from it. I also assume that it bumps
the voltage to a much higher level for the plugs. I've checked the
output of the sealed unit (which leads to the plugs and see no spark.

There's a magnetic switch located next to the fly wheel which closes
briefly on every 1/2 rotation of the flywheel. This appears to
control the timing of the spark and seems to be working fine.

I was leery of taking the flywheel off to expose the stator/rotator as
I don't know how it's assembled and/or what parts might drop off and
how it needs to be aligned. I'm assuming that this is where the
problem is. Any suggestions as to how to proceed and what I need to
be aware of would be greatly appreciated.

-- Geoff


Assume the magnets in the flywheel are OK. They rarely go bad unless
somebody whacks the flywheel with a hammer or something. That being
said, assume the stator coil is bad. It can be checked with an ohm meter
for the proper resistance without removing the flywheel. Find the proper
resistance in the specs and whether or not the stator coil should be
grounded. If it should not be grounded and is grounded then you've
discovered a shorted stator coil. It if is not grounded and should not
be grounded you need to check the resistance to make sure it is within
specs and not shorted internally as in one winding of a wire shorted to
another thus rendering the coils in between ineffective. If you find an
open circuit in the stator it is definitely bad. The stator is just
coils of fine copper wire coated with lacquer insulation wrapped around
an iron core. The magnetism from the flywheel magnets induces an
alternating current in the coil as the North/South magnetic poles rotate
by. It sounds like you probably have capacitor discharge ignition. The
62V box contains all that and may be bad provided the stator tests good.
Or, definitely check the plug wire and plug cap. They often fail.

Wilbur Hubbard