Suzuki 1996 40hp idle inconsistent

[bitsy4643]

1996 suzuki dt40 is slow to start, will idle for 3 or more minutes at 800 rpms, then idle will slowly regress until engine stops. If you turn idle adjustment screw before it dies completely back up to 800 rpms, will run at this rpm speed for a few minutes and then begin picking up rpms to around 1200 + . Readjust idle down to 800 rpms, will idle fine for few minutes until slowly regressing or sropping as before. Carb is immaculate, float set correctly, new fuel needle valve and seat , and all new gaskets. Gas is fresh and has sea foam. Any help greatly appreciated
Idle mixture crew at 1 3/4.