Engine Trouble climbing idle

[wan37]

Yes I have z280 engine run good at first,but the longer you let it idle it starts climbing.It does go high enough I have to shut it down.The bad thing is I tried to spray it with starting fluid but I don't know if its idling high on it's own or if there's a leak there.I have sealed the nt speed carb with gas and oil resistant rtv on the intake and sprayed it afterward it doesn't idle up there.I also used seal all on the engine and intake spot with a new gasket.I'm lost what should I do next?I really am thinking it's a air leak but don't know forsure.Please end this battle for me guys.

 

[KCvale]

Heat will do it, as will having your gas line too close to the head.
If you have closed your gas valve at idle it will rev up as the fuel runs out of as.

 

[wan37]

my gas line is not close to head,so what should I do?Thanks for response