FYI..I just got back from Colorado highcountry with my mule 610. Took it up to a little over 12,000 feet elevation and used a 102 main jet in place of the stock 112 main jet. Ran perfectly and never seemed like it was either too rich or too lean. However it did not want to idle very well cold. The idle air jet really needed to be open more because the idle fuel jet was a little rich at that altitude. Once warm it was fine. Never had to use the choke to start it. Just pat the gas a little to let more air into engine on starting. I was surprised that it ran as well as it did at that altitude.
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