My jato 3.3 will not idle any longer than a few seconds. When I start it up I need to rev the throttle just so the engine does not cut out any ideas on why it's doing this?

Lean the LSN until you get a consistent idle. RTR engines were made to idle for a long time so your tune is way off. When you get your HSN and LSN perfectly tuned lower your idle until it idles stable with the lowest possible idle.

Can I lean the LSN with the engine off?

yes you can lean it with it off. Sounds like you are too rich or not getting enough air. check your idle gap and make sure it's open to .5mm if it is lean it out

turn your lsn a quater turn clockwise. but if it is flush with the carb housing or near that it should be fine.

some other guys might want to chime in but i would lean the hsn first.

i'd check the clutch bearings and springs to see if any are bad.