its not the factory manual, but a Clymer and I'm seeing 1500 (+/- 150 rpm) for idle speed for all yrs . Only mentioning in case you don't find what you're after
Every snowmobile I have ever owned including EFI equip idled around 1800 and my 88 250r is setup to idle between 1800-2000 rpms.When I tell people those numbers they are usually baffled because they are use to looking at there car that idles at 500rpms