1993 Mercury 60 hp 2 stroke has cough/misfire/sputter!

[Disco44]

I need some help trying to figure out what is going on with my merc as it is driving my nuts not being able to figure this out.
Long story short finally had time to clean carbs and attempt to get running for the last part of summer, well all good got it timed, and rpms within spec but dropped in the water for a test spin and ran great except after it warms up and at idle it has a random cough/sputter/misfire??? It does not die, but puffs blue smoke then idles back fine? I posted video below and it happens around the 7/8 second mark, sounds like a thump.

I have checked trigger, stator and they are within specs, alos new plugs, other than that I really do not know what to check further? Maybe carbs aren't right?
Any input would be appreciated

View attachment IMG_2472.MOV

 

[Dave1027]

Could be "Lean pop". A lean mixture can cause a 2 stroke to "pop" or cough. Did you check the fuel pump?

 

[Disco44]

Could be "Lean pop". A lean mixture can cause a 2 stroke to "pop" or cough. Did you check the fuel pump?

Thanks for the reply but yes I beleve it was, adjusted the mixture screws a little and ran for about 20 min without a cough, so maybe I have it dialed in, dropping for a test run this afternoon.

 

[Tech Tony]

The default setting on the mixture screws is 1 and a half turns.