Old beast but has been dependable-until a year ago. Starts right up
and runs like crazy and will die at anytime and will not restart. What
is weird, I can pull the sparkplug, connect it back to the plug boot,
ground the plug on the head and yank the rope starter and has a Hell
of a spark. I then can use starting fluid all I want through the air
filter and cannot get a shot out of it with the plug back in. wtf. I
have tried new plugs, and even a shot of ether in the spark plug hole
and replacing the plug-still cannot get a shot out of it. It appears
the spark won't jump the gap under compression once the igniton
components are warmed up. Leave it overnight and it will fire back up
and may run another 30 minutes or 5 minuters. I am wondering what
ignition part has a pattern failure on this ignition...

Have you checked compression when it refuses to run? Starting fluid would
take almost no spark at all to fire. I wonder if you have a valve problem -
maybe it can't inhale the fuel properly??

"Doc" aol.com> wrote in message
news:b9672e3a-83cb-4f0c-b147-55404cf09680@l17g2000pri.googlegroups.com...

On Apr 29, 8:59 am, "Pieter" plitch.com> wrote:

Motor is a 2 stroke and compression seems to be fine judging by the
way it feels yanking the starting rope with sparkplug installed vs.
removed. Agreed on the starting fluid ability to light off on a weak
spark. I just feel something in the ignition system is laying down
when warmed up from engine heat or activity in the component. Not
unusual for electronics to "open" when warm but work seemingly fine
when cold. Have a Clymer repair manual on order-hopefully it has ohm
checking values for the different ignition components. This motor been
doing this crap for years-so now it will get fixed. I never been a big
fan of electronic ignitions-at least with a point system you can carry
the spare parts in a trail bag and get back home.

ah - a two stroke. That lets us consider a whole 'nuther range of problems
like a blown bas gasket. In addition I've had two stroke snowmobiles with a
tear in the vacuum operated fuel pump that caused eratic fuel delivery to
the carb. Of course, if it is a gravity fed fuel system (overnead fuel
tank), this isn't the problem.

As you point out, this could be a thermal problem in the ignition like a bad
coil (or stator) winding. However, I thought for some reason that your
original post said it had a good spark when the engine was warm and quit
running. If this is the case, it isn't an ignition problem.

My 4 stroke (old) Arctic Cat has an electronic CDI ignition system that has
worked well for 8 years. I am told that they either work or they don't -
rarely do they develop an intermittent problem such as you experience. So
far, so good.