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Discussion Starter #1
All this talk about sleds being jetted too rich from the factory has me thinking. My sled was fouling out during cold starts, but I discovered it was the needle n seat on the PTO side. I've since changed all the needle n seats with genuine Mikuni viton tipped ones.

The sled seemed to run really well, but I'm still wondering if it may be running too rich. It has 270 mains in it, if I remember correctly (I think everything is stock). The E-clip is in the stock (third) postition. I remember checking the plugs, and they looked pretty good, dark cardboard brown. Should I bother trying to raise the E-clip (thus lowering the needle) or just leave it be. Doesn't the needle jet only affect mid range? Ideas? Suggestions? Comments?



1997 XLT SP 600
"Engage the Mechanism"
 

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Yes, the needle effects the midrange. And, if you're getting a dark cardboard brown I'd leave it. That's perfect.

As for the stock mains, do you have the owner's manual (that would surely list the mains to use and when)?? Any stickers under the hood for jetting, perhaps?

On a side note, 270 mains for stock jets (going down to -20°F)?? 270's just seem too small. I certainly could be wrong, but...


1998 Arctic Cat Cougar
1999 Arctic Cat Z 440
1995 Ski Doo Formula STX LT
 

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I read some where that a jetting change from one extreme to another only improved actual horsepower at the engine by 6% on a 100hp machine thats 6hp and at the track thats 3 hp and that was going from 60 degree jetting to 0 degree. Unless you have temp guages I would leave them be.
 

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Discussion Starter #4
No, I don't have the temp guages, so I'll probably leave it alone then. Like I said, it does run real well the way its jetted, I was just curious with all the talk about factory rich jetting. If its not broke, don't fix it right?
Thanks hotrod and ACman.



1997 XLT SP 600
"Engage the Mechanism"
 
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