help with bogging just past idle

[triprop]

pentora 250 with nibbi PE30 that has always run perfect stock. went out and was running great for over 30 minutes and then started to bog real bad just past idle. turned it off waited a couple minutes and started it back up and was running fine, just as i got back to the house it started bogging again. do you think that is more likely a pilot jet or a air/fuel screw thing?