2001 Ski Doo MXZ 600 High Idle

[skutr]

I picked up a 2001 MXZ 600 and when the engine is cold it idles around 1800-2000 and runs smooth but after running around a bit it idles at around 3600-3800 and runs a little rough.

Clutch engages at 4000 and the engine runs smooth with good acceleration through low-mid-high ranges and the back shift/engine braking are good.

I'm thinking the exhaust valves are sticking and need a good cleaning because it idles fine when cold but doesn't after it's warmed up.

Thoughts? Is it just the exhaust valves or should I be looking at other stuff.

 

[skidoodoug]

I have had a 2001 700 do that since new. Just burp the throttle real quick and the idle will go down. I never really worried about it and I have nearly 12000 miles on it.

 

[anonomoose]

That sounds alot like some air leaking in and running rich. If it runs rich, it will idle cold well, but once the machine warms and goes to the leaner mixture, it won't like any air leaking in around boots or any other place it can suck in fresh air causing it to idle high and rough.

If you run it a bunch under lean conditions, you will be looking at a new engine rebuild...find the leaks by checking for cracks in rubber attachments and hoses. A machine of that age is likely to have some cracked rubber somewhere.

Note: Actually I really should say "running lean"....rich is too much gas, lean is when not enough gets to the combustion chamber.

 

[600etec]

I agree with cracked carb boots. Also this motor will do this if the carbs are not clean. Pull the carbs and clean them good. Used compressed air in the the passages for the pilot jets and idol circuit.