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Discussion Starter · #1 ·
My Skidoo 2000 Formula 500 LC is bogging both under load and while up on blocks with no load.

Symptoms:

Under load riding it bogs at speed and over 4000rpm

Under NO LOAD on blocks with track spinning freely it can and will bog at low rpm and then rev up

Facts:

It had some old gas in it (not much), but fired up and ran well. I then added 5 gallons premium 93 to it and ran it some more. Was going great and then started bogging under load after an hour of riding. Never had this issue before.

I have not cleaned carbs or gas lines

Belt is like new and I swapped one out thats new - made no difference

Spark plugs are proper match - I did notice right side cylinder spark plug was pretty dry & clean when I pulled it out. Left side looked more per usual.

I've read as much as I can on this but I'm not sure how to move through a diagnosis.

I've been told it could be a failing clutch? Carb boots? Remove and clean and replace carbs and lines? Check compression? Spark plugs? Coils...

Can anyone recommend a 5 step check this first approach and or diagnosis? Any thoughts greatly appreciated.

-doctordrinks
 

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I'd start by removing the carbs and cleaning them thoroughly. Also inspect all the fuel lines and carb boots for cracks. I'd also suck out all of the gas in the tank and then refill with fresh. Adding fresh gas on top of questionable gas doesn't eliminate the problems posed by old fuel. While you have the carb off and the tank refilled I'd crank it over with the carb fuel supply line off and in a small container to purge the main lines and pump of old gas.

Obviously, a compression test, etc wouldn't hurt if you have the tools.
 

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Discussion Starter · #3 ·
I'd start by removing the carbs and cleaning them thoroughly. Also inspect all the fuel lines and carb boots for cracks. I'd also suck out all of the gas in the tank and then refill with fresh. Adding fresh gas on top of questionable gas doesn't eliminate the problems posed by old fuel. While you have the carb off and the tank refilled I'd crank it over with the carb fuel supply line off and in a small container to purge the main lines and pump of old gas.

Obviously, a compression test, etc wouldn't hurt if you have the tools.
Thank you. Got the carbs out now!
 

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Good luck! I’d recommend replacing the main jet and pilot jet with new ones, they are only a few dollars each. If not then definitely use a very fine wire to clean out all of the passages in each jet.
 

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Discussion Starter · #5 ·
Columbo - jets cleaned .. found a sticky one. fine wire trick worked and cleaned everything and replaced and sounds better than ever. Hoping to get some snow this week to see how it goes! Update after that. Thanks again.
 
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