Okay first off, please forgive me for my sin's on even writing Polaris on this forum
My dad has a Magnum 330, not certain on the year was believed to be a 2003 BUT after stripping the carb down found the jet to be the same size as a factory 2005 not the same size a as a 2003.
The problem is that when warm it struggles to re-start if it dies and if left at idle sped it does die after a minute or so. The other problem is its now backfiring if you pick the revs up and give it some throttle.
We have stripped the carb a few times now, tried various setting on the needle clip, main adjustment screw, float heights, and idle speeds.
Another issue is once the revs are up past 3000rpm and you let off it does not want to come back down, it does eventually lower but only after 5-10 secs.
It is running mega rich, black'ish smoke from over fuelling. This is why it wont start after it dies when hot, if you leave it 5 mins its fires back up again but hezitantly. We have tried to lean it out with the main jet screw and the needle clip but still having the same issue.
Can any one shed any light on what could be causing this, the last thing we can think of is the timing so tomorrow we are going to have a look at the stator plate and timing marks.