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Discussion Starter · #1 ·
I have an 84 Skidoo Formula STX (583 rotary valve Rotax). 10 years ago, I worked for a Skidoo dealer, and this question would have embarassed me... but such is life.

I cannot for the life of me remember the proper steps to synchronizing the carburetors. I know I used to do this all of the time, but like I said, it's been 10 years. The only reason that I am doing this now is because the sled is *very* difficult to start, and does not idle properly. Trying to adjust the idle has caused me to muck it up enough where I just want to start over completely from step one, but I cannot seem to remember the step!! :)

I don't have any synchronizing tools, but I do remember in most cases we didn't even use them, except for triples and extreme cases (pipes, reed changes, etc).

Anyone know of a good website out there that gives a clue?

Thanks!!

Alex
 

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I'll give it a try. Take a drill bit, 1/8" or so and stick it under each slide in turn. Adjust the idle stop till the slide just touches the drill. Do the same for the other carb(s). Adjust the throttle cables till all slides start to move up at the exact same time. They should now be in sync. After you have your machine running, you can adjust both idle stops equally to give the correct idle speed.

One other thing, Don't forget to sync your chokes. I cleaned and synced my carbs several times and just set the choke cables back where they were until looking in the choke passage one time and noticing the little pistons were not in the same position. Adjusted them and wow, easier starting and always starts on both cylinders now.
 

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Discussion Starter · #3 ·
Got it. I tried with the drill bits, but I found something even more accurate:

1. Remove the air box.
2. Hold the throttle wide open.
3. Adjust each cable until the lower side of the slides are even with the throat.
4. Mixture screws: seat and turn both 1.5 turns out.
5. Set the idle screws by holding the throttle at 1500 to 1800rpm and turning the screws in until it starts to idle on it's own, then match the two screw setting to get the proper idle.

Thanks!
 
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