??? on jet sizing.

[hattrk4me]

Ive got a 99 Polaris XC500 Liberty. I'm running rich and I think the jets are not right. I'm running 360 mains currently. any suggestions on the correct jetting size?

[Macgyver55]

Are these the original jets? Did they run properly before or is this something that just started happening. I assume they have been cleaned and adjusted at some point on a sled of that age. Unless you changed something that would cause the motor to need different jets the originals should run right. I hate to give general info, but most sleds will work ok on a jet 1 step leaner.... but then you need to be careful about running it in real cold weather.

[PierBridge]

Nice sled......stock they run awesome.....I own the same sled....I don't believe jetting is your problem....with the limited information it's hard to say, but it sounds like a carburetor or stuck choke....what do the spark plugs look like?????..how old is the gas?.....have the carbs been cleaned or rebuilt?....how many miles?

[hattrk4me]

I bought the sled last Jan. its been that way since I took it off the trailer. test drive was fine. I had a dealership look at it the replace 360 with the 350's. and still ran like dump. Plugs are black (due to running rich?) gas is new, Ive put on about 80 miles so far this year.

Top speed right now is about 55.

[Macgyver55]

Make sure the chokes are releasing fully. Could be a float that is sticking or adjusted too high. Has anyone changed the needle height? And lastly, make sure air intake is unobstructed.

If these things are all ok I'd start looking at other possibilities. It could be that fuel is not the problem but oil could be. If the oiler is set too rich and it will run way better after adjusting it. Check the oiler control cable for free operation and that the oiler lever moves freely. Make sure you check the manual before adjusting the oiler if it needs it.

[PierBridge]

55 MPH....have you had a compression test done? that would help eliminate a bad cylinder.

It could be something as simple as a stuck choke on 1 carb.

To bad your so far away from me, I do know a guy in Otsego that works out of his garage he is real good with Polaris's and has decent rates not sure how busy he is.

[hattrk4me]

seems to me comp was about 140 each side.

[Uncle Bill]

Have you checked the owners manual ??

Some owners manuals list the stock (or production) jet size.

[hattrk4me]

I just remembered something about my sled. When I bought it there was a plunger for the choke in one carb that was broke off. They took a plunger out of a 2005 sled sitting on the show room floor, and put that in mine (a 1999).

Could there be a difference in plunger size? I would figure it would be running rough on one cylinder then, since only one carb is effected.

Attached is a link to a fiche, its parts 10-13

Parts Fiche

[Greg T]

that must have the 2 into 1 choke cable. if the choke plunger was stuck and broke, possibly the cable is messed up on that side as well. the passageway the plunger sits in may be chewed up from removing the old one, i've had that happen before.