I have a 2003 Polaris Pro-X fan that runs rich on the low end when I goose it. Its like it runs on choke.
I got the engine rebuilt and installed an ATTAC and it still runs crappy.
I put hard earned money into fixing it and I don’t want this machine to go to waste, but I’m getting fed up.
Thanks for your email!
If everything else on the engine is okay then there’s little doubt you have a jetting issue.
There’s more than just a main jet in your Mikuni’s and I would suggest you need to look at the Jet needle position (“C” clip) and adjust it accordingly.
If you move the clip up on the needle you go leaner – which is likely what you need to do. However, you should check the jetting chart on your belt guard and make sure you are in the proper main jet range for your altitude and temperature.
Fan cooled sleds are way more sensitive to temperature fluctuations than liquids and thus if you are out a bit on the needle and/or main if the ambient temp goes up it’ll seem like a lot.
As well, you need to look at the air screw. Get a service manual or ask your dealer for help in determining the proper jetting specs.