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550F Freestyle stalling

550F freestyle

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#1 pwdrhnd


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Posted 16 February 2015 - 02:10 PM

I have a 2008 freestyle 550f. The problem is it will stall without warning. Just like the key was turned off. If i flick the key to off then back to start it will fire right up and run. Some times i can get a few hundred feet then it dies again, sometimes it will die as soon as i squeeze the throttle. This usually happens more after it has come out of the heated shop than when it was sitting outside. It generally runs for anywhere from 3-20 miles before it will start to act up. I replaced the ignition switch already.The kill switch seems to work fine. But i haven't unhooked it for a ride yet. Just wondering if anyone has an idea what i should try next?

#2 irondoo


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Posted 16 February 2015 - 02:49 PM

There are several components to the fan two-stroke iginiton system.  The alternator (coil) in the flywheel housing,  the

computer/CDI/high tension transformers with wires to the plugs, and the "operator controls."


Operator controls include the ignition key switch on the right handlebar grip.


The operator controls work by shorting the one wire to ground to kill the engine.  If the wire was to break, the

engine would continue to run even if that particular switch was turned to off.  This is the reverse of 4-stroke

and automobile ignition systems that pass wire thru the switch.   In the automotive application, the switch

is OPEN for the engine to be off; in the 2-stroke the switch is CLOSED for the engine off, and open for the

engine to run.


This makes it kinda easy to troubleshoot.  Just disconnect this ignition control wire as close as possible to

the engine.  I do not have the 2008 schematic (only the 2007),  but if you look at the wiring diagram you can

see where the wire can be opened up: at a connector closes to the engine as possible.  That would allow the

engine to run.  To turn it off, you can usually just choke the engine to kill it, or pull the plug wires (not

recommended as it stresses the coils).


If this cures your problems, then the problem is in the wiring or switches.  There are numerous places where

it can short to ground, but a harness problem is rare.  Given your symptoms, it COULD be a wire that has

chaffed on a piece of metal.  A momentary short would kill the engine.  This is easy to fix, and should be your

first troubleshooting step.  It will cost almost nothing to fix, but might be hard to pin down. 


Assuming the engine still has trouble with the garbage wiring disconnected, then the problem is either

in the CDI/Computer module or the power coming from the alternator stator coil.  Again, you can

investigate this.  Best bet is to borrow a KNOWN WORKING module.  Just because you buy a brand new

one does not mean it's good.  A friends that can loan it to you is best.  You will only need it for a single



Lets say you do the swap, go for a ride, all is good.  Do you then buy a new module?  NO!  Switch your old

one back in to reconfirm.  It may be that disturbing the wiring is what fixed it, so confirm both ways.

Old ... New ... Back to Old.  


If it does not fix the problem, then the culprit is likely the wiring TO or WITHIN the flywheel housing.

This is nasty to troubleshoot and fix, but you may spot a crumbly wire terminal, etc. outside of the



My guess: it is most likely the Module.  Why?  Because it is temperature/moisture related and this type

of trouble is common on the 300F and 550F ignition modules.  A pinhole or crack in the module allows

some moisture in, and all sorts of mischief occur within the module.  That water droplet runs around,

turns to vapor, recondenses, or starts a high voltage arc.  An arc is always harder to start than to

sustain, so the moment the engine goes off, the arc goes away and you are good to go for a while.

But that module is expensive, so you should eliminate the other possibilities first before you go throwing

good money after bad.  I strongly suggest you borrow someone's module to test the theory with.

Please make sure it is a known working one.  In other words, from an engine you SEE run, not take his

word for it: "Oh, this engine was running fine three years ago when the track went out and I parked it."

Greetings from Nome, Alaska, USA

#3 pwdrhnd


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Posted 17 February 2015 - 09:47 AM

Thanks for the advice. I will have a closer look at the wiring first then go from there.

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