DPM varies float bowl pressure to adjust for both altitude and temperature. It sits above the carbs, a round black plastic case with tubes running out of it that run to the carbs. Can be tested with a 9v battery and paper clip - Dootalk will have instructions on how to do this if you're interested. On older sleds, the pressure lines will crack and leak. I know that all early renegades had it, at least. I owned two gades and four summits with DPM. Jets work the same, but be careful - there is little leeway if you have DPM between safe and lean when you rejet, especially at lower elevations. On summits with DPM I would only shim the needles to get spot on in the midrange - the rest of fuel curve was very good. When DPM fails it runs full rich. It was very effective and innovative - originally developed for the ultralight aircraft motors. First, confirm you have it. Should be a decal on the hood if the stock decals are in place. Doo's site will have specs for older sleds that should list it, too.
