I have an 1982 150 Johnson V-6. At open throttle engine began to intermitantly loose power. No problem with idle or nuetral to gear stalling. Changed fuel tank from boat to carry on with new fuel.No Fix. Cleaned Carbs / Filter, Changed spark plugs (slightly wet & oily). Manual Spec'd Champion UL-77V I used QL16V per Boat-Us. Checked Spark and replaced 3 coils,now all have spark but weak.Getting fuel to plugs.Now Motor starts good & runs strong (high rpms) in throttle only, alot of white smoke.It runs rough at low rpms sputters and regains rpms until it stalls out after a few minutes, and it stalls out at low idle/ neutral.